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T L Spray

Publications and source records attributed to T L Spray.

At least 145 records · Page 8Linked to original sources
PubMed1982

Ribose-enhanced myocardial recovery following ischemia in the isolated working rat heart.

Recovery for myocardial adenosine triphosphate (ATP) following moderate periods of ischemic is dependent upon the availability of adenosine monophosphate (AMP) and diphosphate (ADP) for rephosphorylation. Recovery of AMP and ADP levels following ischemia is, in turn, determined by the rates of salvage and de novo adenine nucleotide synthesis. Phosphoribosyl pyrophosphate (PRPP) availability is rate limiting in both salvage and de novo adenine nucleotide synthesis. Parenteral ribose infusions in rats have been documented to elevate myocardial PRPP levels with resultant enhancement of adenine nucleotide synthesis. In this study postischemic recovery of myocardial function and ATP levels in isolated, working rat hearts given ribose infusions before and after ischemia was compared with recovery in control hearts subjected to the same protocol without ribose administration. The mean percent of functional recovery in control hearts following 15 minutes of warm ischemia reached values of 56.7 +/- 4.1%, 63.5% +/- 4.3%, 65.9% +/- 4.6%, and 70.5% +/- 4.7% at 2, 5, 10, and 15 minutes of work following ischemia. Hearts perfused with ribose demonstrated improved mean percent return of function at similar intervals of postischemic work with values of 67.9% +/- 4.2%, 73.7% +/- 3.7%, 81.0% +/- 3.5% (* = p less than 0.02 versus control) *and 85.4% +/- 3.3%, *respectively. Determinations of myocardial ATP levels (mumoles/gm of dry weight) made at the end of 15 minutes of postischemic work were significantly higher (p less than 0.02) in the ribose-treated hearts (18.9 +/- 0.7) than in controls (16.3 +/- 0.6). Infusion of ribose before and after ischemia is a biochemically logical method of improving postischemic myocardial ATP and functional recovery by manipulation of adenine nucleotide synthetic pathways.

Adenine Nucleotides↗
PubMed1981

Transmural gradient in high-energy phosphate content in patients with coronary artery disease.

In 16 patients undergoing elective coronary artery bypass, transmural biopsies were performed during bypass but before global ischemia. Subendocardial and subepicardial halves were separately assayed in each sampled tissue. Adenosine triphosphate (ATP) levels, total adenine nucleotide content (sigma Ad), and creatine phosphate (CP) content were significantly higher (p less than 0.005) in the subepicardium than the subendocardium in regions of the heart distal to major occlusions: 35.36 +/- 2.12 nmole/mg versus 28.7 +/- 1.7 (ATP), 42.24 +/- 2.04 versus 35.6 +/- 1.6 (sigma Ad), and 29.99 +/- 4.32 +/- versus 16.35 +/- 3.48 (CP). The opposite was true in two hearts with normal coronary arteries, in which high-energy phosphates tended to be higher in the subendocardium than the subepicardium. A transmural metabolic gradient therefore exists in regions of the myocardium distal to significant coronary occlusive disease. The subendocardium's relative depression in metabolic reserve cold determine its susceptibility to ischemic damage and influence techniques designed to preserve the heart during ischemia.

Adenine Nucleotides↗
PubMed1979

Infection of glutaraldehyde-preserved porcine valve heterografts.

Gross, histologic and ultrastructural changes associated with bacterial infection are described in four porcine valve heterografts that had been in place in patients for 6 days to 28 months. In one patient, culture of the aortic tissue tag included in the heterograft container grew Mycobacterium chelonei; however, examination of the heterograft, recovered at necropsy 6 days after implantation, revealed small colonies of bacteria that differed morphologically from mycobacteria. A second heterograft was the site of staphylococcal infection associated with extensive destruction of collagen in the leaflets. Similar destruction was observed in a third heterograft, which was found to have organisms on ultrastructural study even though bacterial cultures of the valve were negative. The fourth heterograft, from a patient who died of coronary embolism secondary to dislodgment of vegetative material, contained structures resembling lysed bacteria. Observations in these 4 patients and review of published reports of infection involving 43 other patients with porcine valve heterografts indicates that infection in these valves: (1) develops in the fibrin layer that covers the cusps, (2) can involve the collagen in the leaflets, and (3) is uncommonly (three patients) associated with valve ring abscesses.

Adult↗
PubMed1978

Structural changes in glutaraldehyde-treated porcine heterografts used as substitute cardiac valves. Transmission and scanning electron microscopic observations in 12 patients.

Scanning and transmission electron microscopic studies were made of (1) 12 glutaraldehyde-treated porcine valvular heterografts that had been implanted in patients for 2 days to 76 months; (2) 3 unimplanted commercially processed porcine aortic valves; and (3) 1 unprocessed porcine aortic valve. Comparison of unprocessed porcine valves and unimplanted commercially processed valves showed loss of endothelium and acid mucopolysaccharides during preimplantation processing. Short-term (less than 2 months) changes after implantation consisted of insudation of plasma proteins, penetration of erythrocytes into surface crevices, formation of a thin surface layer of fibrin, and deposition of macrophages, giant cells and a few platelets. Longer-term (more than 2 months) changes were proportional to the time interval after implantation and consisted of progressive disruption of collagen, erosion of the valve surfaces, formation of aggregates of platelets and accumulation of lipid. The surfaces of the leaflets did not become covered with endothelium or with a fibrous sheath. Calcific deposits were found in one valve and bacterial organisms in another. Thus, progressive breakdown of collagen appears to be a critical factor in determining the long-term durability of glutaraldehyde-treated porcine valvular heterografts.

Adult↗
PubMed1978

Ventricular pseudoaneurysm after transaortic septal myotomy for hypertrophic subaortic stenosis.

Clinical and morphological features are described in a man in whom a pseudoaneurysm arising from the ventricular septum developed after transaortic septotomy for hypertrophic subaortic stenosis. Pseudoaneurysm of the left ventricle or ventricular septum has not been described previously in a patient with hypertrophic cardiomyopathy in whom only the transaortic approach was utilized for septotomy or septectomy or both. In addition, no previous studies have reported pseudoaneurysm arising from the ventricular septum.

Aortic Valve↗
PubMed1978

Prosthetic-valve endocarditis due to Listeria monocytogenes.

Clinical and necropsy observations in the case of a patient with prosthetic-valve endocarditis due to Listeria monocytogenes are presented. Although rare cases of L. monocytogenes infection of natural cardiac valves have been reported, this represents the first known case of infection of a prosthetic cardiac valve by this organism.

Aortic Valve↗
PubMed1978

Structural changes in Hancock porcine xenograft cardiac valve bioprostheses.

Gross and histologic observations are described in 51 Hancock glutaraldehyde-preserved porcine heterograft bioprostheses from 41 patients: 33 valves from 25 patients had been in place for less than 2 months (early) and 18 valves from 17 patients were examined at later periods up to 75 months (late) after implantation. The major gross changes were cuspal thrombosis (5 bioprostheses) and cuspal degeneration (3 bioprostheses). Major histologic changes observed in 44 bioprostheses (26 early and 18 late) examined histologically were: (1) fibrin deposits on inflow and outflow surfaces of the cusps; (2) inflammatory cell infiltrates; (3) histiocyte deposition; (4) giant cell formation, and (5) focal disruption of the fibrocollagenous structure of the cusps. These observations indicate that porcine bioprostheses are not biologically inert in the human circulation. Valve failure, however, is rare at the implantation periods studied.

Animals↗
PubMed1978

Ultrastructure of Hancock porcine valvular heterografts. Pre- and post-implantation changes.

Scanning and transmission electron microscopic studies were made of: 1) 15 glutaraldehyde-treated porcine valvular heterografts that had been implanted in patients for periods of time ranging from 2 days to 76 months; 2) unimplanted, commercially processed porcine aortic valves; and 3) unprocessed porcine aortic valves. Unimplanted, commercially processed valves showed loss of endothelium and acid mucopolysaccharides. Short-term (< 2 months) post-implantation changes consisted of insudation of plasma proteins, penetration of erythrocytes into surface crevices, formation of a thin surface layer of fibrin, and deposition of macrophages, giant cells and a few platelets. Longer term (> 2 months) changes consisted of progressive disruption of collagen, erosion of valvular surfaces, formation of aggregates of platelets, and accumulation of lipid. The surfaces of the leaflets did not become covered with endothelium or with a fibrous sheath. It is concluded that progressive breakdown of collagen is a critical factor in determining the long-term durability of glutaraldehyde-treated porcine valvular heterografts.

Animals↗
PubMed1977

Structural changes in porcine xenografts used as substitute cardiac valves. Gross and histologic observations in 51 glutaraldehyde-preserved Hancock valves in 41 patients.

Gross and histologic changes are described in 51 Hancock glutaraldehyde-preserved porcine heterograft bioprostheses from 41 patients: 33 valves from 25 patients had been in place for less than 2 months ("early") and 18 valves from 17 patients were examined at later periods up to 75 months ("late") after implantation. The major gross changes were thrombosis (five bioprostheses) and degeneration (three bioprotheses) of the cusps. Major histologic changes observed in 44 bioprostheses (26 early and 18 late) examined histologically were: (1) fibrin deposits on inflow and outflow surfaces of the cusps; (2) inflammatory cell infiltrates; (3) histiocyte deposition; (4) giant cell formation, and (5) focal disruption of the fibrocollagenous structure of the cusps. These observations indicate that porcine bioprostheses are not biologically inert in the human circulation. However, valve failure is rare at the implantation periods studied.

Animals↗
PubMed1977

Medial calcinosis of Mönckeberg. A review of the problem and a description of a patient with involvement of peripheral, visceral and coronary arteries.

Massive medial calcific deposits (Mönckeberg's calcinosis) are described in the peripheral and visceral arteries, and similar but small-sized deposits in the coronary arteries of a 41 year old woman with diabetes mellitus. Although observed by roentgenogram fairly commonly during life in the muscular arteries of the legs in middle-aged men, medial calcinosis infrequently involves the visceral arteries and has never, to our knowledge, been documented in the coronary arteries. Although it may be associated with intimal atherosclerosis, medial calcinosis, per se, does not obstruct the lumens of the arteries and, therefore, does not lead to symptoms or signs of limb or organ ischemia. The cause of medial calcinosis remains a mystery, but it appears to affect people with diabetes more frequently than those without.

Adult↗
PubMed1977

Pericardial heart disease.

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 3 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 acut eillness. Even when clinical symptoms are present, however, fewpatients 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.

Acute Disease↗
PubMed1977

Changes in saphenous veins used as aortocoronary bypass grafts.

This report describes morphologic changes in saphenous veins used as aortocoronary bypass conduits, and discusses the relative contribution of various factors to these changes. The three primary changes are: (1) medial fibrous replacement, (2) adventitial fibrous proliferation, and (3) intimal fibrous proliferation. Medial fibrous replacement is caused by vein wall ischemia with loss of smooth muscle cells; adventitial fibrous proliferation is the result of organization of fibrin deposits and repair of ischemic injury; and intimal fibrous proliferation results from some stimulus, probably fibrin deposition on injured intima, which causes stimulation of smooth muscle cells to become fibroblasts or "myointimal cells". Although all grafts show some changes, the degree and severity of these three changes is variable along the length of the grafts and among separate grafts in the same patient.

Adult↗
PubMed1977

Status of the grafts and the native coronary arteries proximal and distal to coronary anastomotic sites of aortocoronary bypass grafts.

The status of the native coronary arteries at necropsy in the vicinity of the coronary anastomoses of saphenous vein aortocoronary bypass grafts in 20 patients with severe coronary heart disease is presented. Of the 37 graft systems (graft plus coronary artery into which graft inserted) analyzed, the lumina of 44% of the native coronary arteries within the first 2 cm distal to the anastomoses were greater than 75% narrowed in cross-sectional area by atherosclerotic plaques, and the native coronary artery at the site of the anastomosis was greater than 50% narrowed in cross-sectional area already by atheroclerotic plaque in 25% of the graft systems. The mean coronary arterial size distal to the site of the coronary graft anastomosis, even after correction for heart weight, was greater in the 13 men than in the seven women. The residual luminal areas squared per gram of heart weight, however, were similar in both men and women. These results suggest that 1) relative coronary vessel size is greater in men than women; 2) the luminal area squared per gram myocardial mass (a relative estimation of flow) is the same in the two groups of patients; and 3) less atherosclerotic plaque is necessary in women then in men to produce similar limitation to coronary flow. Thus, vessel size alone cannot account for the higher reported frequency of unsuccessful aortocoronary bypass procedures in women.

Adult↗
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↗
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↗