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Biomedical subjects

M C Fishbein

Publications and source records attributed to M C Fishbein.

At least 253 records · Page 14Linked to original sources
PubMed1978

Experimental myocardial infarction in the rat: qualitative and quantitative changes during pathologic evolution.

Surgical occlusion of the left coronary artery of the rat is a relatively simple, economical technique for producing experimental myocardial infarction (MI). Histologic study of 1- to 21-day-old MI in rats showed that following a mild and brief acute inflammatory response at the margins of the necrotic myocardium, there is chronic inflammation, vascular and collagenous proliferation, and resorption of necrostic tissue which progresses until scar formation is complete, usually by 21 days. From Day 1 to Day 21 the volume of infarcted myocardium decreases from 45.9 +/- 5.9% (mean +/- SEM) to 26.1 +/- 3.2% of the left ventricle and infarct thickness decreases from 1.30 +/- 0.06 mm to 0.47 +/- 0.02 mm. Concomitantly, the percent of the surface area of the left ventricle which is infarcted decreases insignificantly from 55.7 +/- 7.2% to 48.3 +/- 4.2%, indicating that the decrease in volume of the infarcted tissue occurs primarily as a result of thinning of the MI. This study provides qualitative and quantitative information on the natural history of MI in rats, which should be useful as a baseline for future studies.

Animals↗
PubMed1978

Radionuclide scintigraphy in the evaluation of ventricular septal defect complicating acute myocardial infarction.

A 67-year-old man with an autopsy-proven ventricular septal defect (VSD) following an acute inferoposterior myocardial infarction underwent bedside evaluation by radionuclide imaging techniques. The presence of the VSD was confirmed, and the size of the shunt determined by qualitative and quantitative radionuclide angiocardiography. In addition, radionuclide ventriculography permitted assessment of global as well as regional left ventricular function.

Aged↗
PubMed1977

Cardiac pathology of transvenous pacemakers in dogs.

Transvenous right ventricular pacemaker catheters were implanted in 18 mongrel dogs for periods of 2 to 18 months (average 4.9 months). Heart block was produced in 15 of these dogs by injection of 37 per cent formaldehyde into the interatrial septum. In the other three dogs which served as controls, no heart block was produced and no electrical stimulation was applied to the implanted catheters. After the animals had been put to death, gross and microscopic examination of the hearts revealed four categories of morphological changes: (1) connective tissue sheath formation around the catheters, (2) endocardial papillary thickening, (3) interatrial septal changes, and (4) myocardial damage. Changes 1, 2, and 4 occurred in one or more intracardiac locations in all 18 dogs. Change 3 occurred only in the 15 dogs in which heart block was produced. The most striking histologic findings were areas of cartilagenous metaplasia in endocardium an underlying myocardium and areas of marked cellular proliferation of the endocardial cells both in the endothelium and underlying stroma. Chronic implantation of transvenous intracardiac pacemaker catheters in dogs consistently produces morphologic changes which may interfere with cardiac and pacemaker function and may hinder attempts to remove nonfunctional or unneeded catheter electrodes. The changes observed appear to be related to the presence of foreign material per se and not external electrical stimulation of the heart.

Animals↗
PubMed1977

The effect of propranolol on microvascular injury in acute myocardial ischemia.

The purpose of this study was to determine whether propranolol, which has been shown to reduce the extent of myocardial infarction, reduces microvascular injury which may play a role in exacerbating ischemia. Saline (10 dogs) or propranolol (2 mg/kg i.v., 7 dogs) was injected prior to a one hour occlusion of the left anterior descending coronary artery. Carbon black (1 ml/kg), which labels damaged and leaky vessels, was injected 5 min after release of the occlusion and allowed to circulate for two hours. By morphometric analysis of 1 micron thick sections, 75 +/- 12% of vessels and 84 +/- 7% of myocardial cells showed damage in untreated dogs; only 2 +/- 1% of vessels and 9 +/- 8% of myocardial cells showed damage in the propranolol-treated dogs (P less than 0.001). The number of carbon black-labeled vessels/10 fields/biopsy from comparable areas of ischemic tissue was 55 +/- 7 in untreated dogs and 27 +/- 3 in propranolol-treated dogs (P less than 0.001). The results suggest that propranolol not only protects the ischemic myocardial cell, but also significantly decreases the ischemic microvascular changes.

Acute Disease↗
PubMed1977

Pseudoaneurysm of the left ventricle: an unusual echocardiographic presentation. Review of the literature.

Echocardiography showed a large anterior chamber communicating with the left ventricle cavity through the interventricular septum in a patient with a previous left ventricular aneurysmectomy. At postmortem examination this chamber proved to be an 11-cm diameter pseudoaneurysm that opened into the left ventricle through a 3-cm orifice. A review of the literature showed 67 cases of histologically proven left ventricular pseudoaneurysm, most of which occurred after myocardial infarction and cardiac surgery. Twenty-six of 32 left ventricular pseudoaneurysms were successfully operated upon. Among 35 patients with pseudoaneurysms not operated upon, rupture was a cause of death in 11.

Autopsy↗
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↗
PubMed1976

Hyaluronidase-induced reductions in myocardial infarct size.

The size of myocardial infarctions following coronary artery occlusion in the rat was determined directly by measurement of creatine phosphokinase activity in homogenized whole left ventricles and by planimetric measurement of the area of the infarctions in histologic sections of serial slices of the left ventricles. Hyaluronidase was shown to produce significant reductions in expected infarct size both 48 hours and 3 weeks after occlusion without impairing fibrosis during the healing phase. Thus, the amount of myocardial necrosis that follows a coronary artery occlusion has been shown directly to be amenable to reduction with a pharmacological intervention.

Animals↗
PubMed1976

Use of changes in the epicardial QRS complex to assess interventions which modify the extent of myocardial necrosis following coronary artery occlusion.

The goal of this study was to determine if changes in the epicardial QRS complex after coronary artery occlusion (CAO) can be used to evaluate the efficacy of interventions designed to limit infarct size. Forty-one open-chest dogs with CAO were studied: 15 were controls, 18 received hyaluronidase and eight received propranolol starting 20 minutes after CAO. Epicardial ECGs were recorded at specific time intervals to analyze ST-segment elevation and changes in Q and R waves. Transmural specimens were obtained 24 hours after CAO from the same sites at which ECGs were recorded. Q wave development (deltaQ), R wave fall (deltaR), and their combination (deltaR + deltaQ) at 24 hours correlated with the extent of necrosis, as determined by myocardial creatine phosphokinase activity depression and histologic appearance. In the control group ST-segment elevation 15 minutes after CAO (ST15M) predicted changes in Q and R waves 24 hours later; in the treated groups, the same ST15M prior to drug administration resulted in significantly less QRS changes. Thus, 1) Q wave development and R wave fall 24 hours after CAO accurately reflect myocardial necrosis. 2) ST15M predicts subsequent changes in Q and R waves. 3) The efficacy of hyaluronidase and propranolol, agents previously shown to reduce myocardial necrosis, can be detected by less Q wave development and a smaller fall in R wave voltage.

Animals↗
PubMed1975

Abdominal cystic lymphangiomatosis: report of a case involving the liver and spleen and illustration of two cases with origin in the greater omentum and root of the mesentery.

B-scan ultrasonic examination of a 10-year-old Mexican-American female with multiple avascular hepatic and splenic defects on both isotopic and angiographic evaluation revealed numerous cystic lesions, a few of which contained numerous internal echoes. Subsequent pathological examination revealed lymphangiomatosis of the liver and spleen. Some of the cysts contained caseous material as predicted only by the ultrasonic examination. Cystic lymphangiomatosis of the spleen is a rare condition and only a few cases of involvement of both the spleen and liver have reported. This is the first such case evaluated by ultrasound. Two cases are also illustrated of cystic lymphangiomatosis with origin in the greater omentum and root of the mesentery.

Adolescent↗
PubMed1975

Cardiac pathology after aortic valve replacement using Hufnagel trileaflet prostheses: a study of 20 necropsy patients.

Necropsy observations are described in 20 patients dying between October 1967 and March 1973 after replacement of the aortic valve with a Hufnagel trileaflet prosthesis. Seven patients died within two months of operation and 13, between 2.1 and 58 months (average 22). Four of seven patients dying early had extensive prosthetic thrombus causing obstruction of one coronary arterial ostium in each. Of the 12 patients surviving six months or longer after valve replacement, death in eight resulted from degeneration (tearing) of the prosthetic cusps causing severe aortic regurgitation in each, and from thrombosis of the prostheses in three, probably causing prosthetic stenosis and defintely causing narrowing of at least one coronary ostium. Thus, prosthetic degeneration or thrombosis caused death in 11 of the 12 patients surviving six months or longer. In conclusion, this trileaflet aortic prosthesis, although similar in design to the normal aortic valve, is composed of materials not durable enough to withstand the stresses created by blood flow in this position.

Adult↗
PubMed1975

Cardiac pathology after valve replacement by disc prosthesis. A study of 61 necropsy patients.

Clinical and necropsy observations are described in 61 patients who had one or more cardiac valves replaced with a discoid prosthesis of the Hufnagel type. The most common (31 percent) cause of death among the 45 patients who died early (less than 65 days after operation) appeared to be prosthetic disproportion; that is, the prothesis was too big for the aorta or ventricular cavity into which it was inserted so that inadequate space was present between the margins of the disc and the endocardium of ventricle or intima of aorta. Prosthetic thrombosis occurred in only 3 of the 45 patients who died early, but poppet movement appeared considerably altered in each. In contrast, thrombi were observed on a prosthesis in 14 of the 16 patients who died late (4 to 47 months [average 21] postoperatively), but in none did the thrombi appear of sufficient size to alter poppet function. Escessive bleeding occurred in 11 (24 percent) of the 45 early deaths and was primarily related to the insertion of a patch in the root of the aorta. Uncorrected valvular disease either by itself or by its ability to alter function of the prosthesis appeared responsible for death in 6 (13 percent) of the 45 patients who died early and in 2 (6 percent) of the 16 who died late. Insertion of a mitral poppet disc in a patient with uncorrected aortic regurgitation, even of mild degree, may be hazardous because the aortic regurgitant jet stream may interfere with proper function of the mitral disc. Likewise, insertion of a poppet disc only in the aortic valve position in a patient with combined aortic and mitral regurgitation may considerably increase the degree of mitral incompetence because the aortic prosthesis is intrinsically obstructive. Disc wear or variance was observed in all but one prosthesis in place for more than 1 year. Although hemolytic anemia of significant degree was not observed in any of the 16 patients who died late, the occurrence of renal hemosiderosis in 13 of the 16 patients indicates that the poppet disc prosthesis is considerably traumatic to erythrocytes. Thus, this type of prosthesis is not an ideal substitute cardiac valve. It clots, despite anticoagulant therapy, it is intrinsically stenotic, portions of it, that is, the disc, degenerate, and it causes hemolysis to erythrocytes.

Adult↗
PubMed1975

Unruptured sinus of Valsalva aneurysm.

An unruptured congenital sinus of Valsalva aneurysm (behind the right aortic valve cusp) is described as an incidental necropsy finding in an 82 year old man. Review of previous reports on aneurysms involving only one of the three aortic sinuses discloses that few cases have been described, and that these lesions are rarely diagnosed during life. It is probable, however, that unruptured aortic sinus aneurysm (involving only one sinus) is more common than previous reports indicate, but that, among patients with congenital sinus aneurysm, rupture is likely to occur.

Aged↗
PubMed1975

Late postoperative anatomic observations after insertion of Hufnagel caged-ball prostheses in descending thoracic aorta.

Clinical and necropsy observations are described in two patients who died 11 and 13 years, respectively, after implantation of Hufnagel prostheses (the first ever used successfully in humans to treat cardiac valve disease) in descending thoracic aorta. Despite the long implantation periods, there was no evidence of prosthetic degeneration or thrombosis or intravascular hemolysis. Although approximately 4000 Hufnagel descending aortic prostheses were distributed by the manufacturer for human use, data in only 55 patients in whom these prostheses were inserted were found in previous publications, and 26 of them had died. Of the 13 late deaths previously reported, no evidence of prosthetic degeneration or thrombosis was described in the three patients surviving greater than 3 years (8, 10, 12.5 years, respectively). Since neither our patients nor any of the other three reported long-term survivors had prosthetic-related complications and since the dangers of excising the descending aortic prosthesis are considerable, it appears most reasonable, as a rule, not to remove the descending aortic prosthesis at any time in these patients if aortic valve replacement is subsequently performed.

Adult↗
PubMed1975

Endocardial papillary elastofibromas. Histologic, histochemical, and electron microscopical findings.

The organization of cellular and extracellular components appeared similar and was distinctive in three endocardial papillary elastofibromas studied. Each tumor papilla contained (1) a dense, central core of collagen and elastic tissue, (2) a peripheral, myxomatous layer with deposits of acid mucopolysaccharides, and (3) an overlying, hyperplastic layer of endothelial cells. Ultrastructural study of one tumor showed that the cells in all three zones had numerous cytoplasmic filaments, 100 Angstroms in diameter, and dilated cisterns of endoplasmic reticulum; endothelial cells also had intercellular junctions and numerous pinocytotic vesicles. The myxomatous stroma varied from amorphous to fibrillar, and the collagenous cores showed focal degeneration. The name "endocardial papillary elastofibroma" is suggested to emphasize those features which are most conspicuous and which serve to differentiate this tumor from myxoma.

Endocardium↗