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Query: UMLS:C0729233 (Thoracic)
 6,478 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Thoracic aortae of normal rabbits were perfused with pancreatic elastase in vitro at 37 degrees C and 70 mm Hg pressure in the presence or absence of elastin ligands previously shown to stimulate or inhibit the enzymatic degradation of elastin. Perfusion with elastase results in an average of 3.6 lamellae degraded, whereas addition of sodium linoleate before and during the perfusion with elastase increases this value to 7.9 (P less than 0.001). Conversely, perfusion with the cationic detergent, dodecyltrimethylammonium chloride, completely prevents the degradation of elastic lamellae by elastase. These effects do not reflect alterations of the intrinsic catalytic activity of elastase, but apparently indicate the formation of complexes between the elastin ligands and arterial elastic lamellae, as is consistent with prior studies indicating such interactions between fatty acids or detergents and purified elastin. These studies suggest that agents such as fatty acids may significantly alter the metabolic susceptibility of elastin in vivo and possibly contribute to the degradation of elastic lamellae seen in arteries with advanced atherosclerosis.
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PMID:A possible role for elastin ligands in the proteolytic degradation of arterial elastic lamellae in the rabbit. 75 37

This study was undertaken to examine the alterations in vascular relaxation responsiveness to endothelium-dependent or -independent vasodilators, including atrial natriuretic peptide (ANP) and acetylcholine, in aortas of Watanabe heritable hyperlipidemic (WHHL) rabbits during the progression of the atherosclerotic plaque. WHHL rabbits were divided into two groups according to age: group 1, 6-11 months, and group 2, 12-18 months. The isolated thoracic aortas obtained from both normal (control) and WHHL rabbits were suspended in a bath containing oxygenated Krebs' buffer for recording of isometric force. The endothelium-dependent relaxation evoked by acetylcholine was reduced in group 1 WHHL rabbits and decreased progressively in proportion to the degree of atherosclerosis progression when compared with age-matched control rabbits. ANP-induced relaxation was not significantly decreased in group 1 WHHL rabbits. However, ANP-induced relaxation was markedly impaired in group 2 WHHL rabbits. Thoracic aortas with severe atherosclerosis were less sensitive to ANP, with a significant increase in the median effective dose, although maximum relaxation induced by ANP was not reduced. Accumulation of cyclic GMP induced by ANP and acetylcholine was markedly reduced in atherosclerotic arteries obtained from group 2 WHHL rabbits compared with control rabbits. Vascular relaxation elicited by nitroglycerin or isoproterenol was not significantly impaired in atherosclerotic arteries from either group 1 or group 2 WHHL rabbits. From these results, we suggest that ANP-induced cyclic GMP formation and vascular relaxation via particulate guanylate cyclase in vascular smooth muscle cells are impaired in severely atherosclerotic arteries.
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PMID:Impaired vasodilatory response to atrial natriuretic peptide during atherosclerosis progression. 131 25

Over a 40 year period (1950-1990) only 73 patients were treated surgically for brachiocephalic aneurysms. An operation was performed for 38 subclavian, 25 extracranial carotid, six innominate, three aberrant right subclavian, and one vertebral artery aneurysm. Twenty-three other associated aneurysms occurred in 14 patients. Five patients had an additional untreated brachiocephalic aneurysm, and nine patients had 18 aneurysms located in different anatomic regions. There were 40 men and 33 women with a mean age of 50.5 years (range 16 to 82 years). Forty patients (54.8%) presented with potentially life- or limb-threatening signs or symptoms, including stroke or transient ischemic attacks (31.5%), upper extremity ischemia (19.2%), and rupture (4.1%). Atherosclerosis was most common in innominate aneurysms (66.7%) but also occurred in subclavian (34.1%) and carotid aneurysms (12.0%). Thoracic outlet compression was a common etiology for subclavian aneurysms while trauma or spontaneous dissection was more frequent for carotid aneurysms. Six deaths (8.2%) occurred within 30 days of operation: two from rupture, three in association with concomitant cardiovascular operations, and one from emergency carotid ligation. There were no deaths with elective isolated surgical repair. Overall five and 10 year survival in patients with brachiocephalic aneurysms was 80.8% and 61.4%, respectively. The majority of brachiocephalic aneurysms present with life- or limb-threatening complications and are associated with a high mortality for emergency or concomitant repair. Early elective isolated surgical repair remains the optimal therapy.
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PMID:Brachiocephalic aneurysm: the case for early recognition and repair. 201 82

Dietary marine oil supplements may protect against atherosclerosis, although their influence on plasma lipids, in vivo cholesterol metabolism, and aortic cholesterol accumulation remains uncertain. The effects of daily administration of marine oil--delivering 100 mg of eicosapentaenoic acid, 59 mg of docosahexaenoic acid, and 221 mg of omega-3 fatty acids per kilogram--were assessed in 33 New Zealand white rabbits. Six animals (group I) were immediately killed. In the remaining animals stable hypercholesterolemia was induced with a 0.25% cholesterol-enriched diet. After 7 weeks on this diet, six animals were killed (group II). Total plasma cholesterol had increased significantly (982 +/- 119 mg/dl vs. 55.6 +/- 7.1 mg/dl, mean +/- SEM, p less than 0.001). The remaining animals randomly received a tap-water placebo (group III, n = 12) or marine oil (group IV, n = 9) daily. After 3 months, total plasma cholesterol was similar (p = NS) among group II (982 +/- 119 mg/dl), group III (965 +/- 54 mg/dl), and group IV (913 +/- 46 mg/dl). No significant differences in HDL cholesterol, LDL cholesterol, VLDL cholesterol, or triglyceride levels developed between the placebo and marine oil groups. Two-hour, hepatic total lipid, neutral steroid, fatty acid, bile acid, and cholesterol synthesis rates were not significantly affected by marine oil treatment. Thoracic aortic cholesterol content increased during cholesterol feeding (5.7 +/- 0.9 mg/gm vs. 1.1 +/- 0.05 mg/gm, group II vs. group I, p less than 0.05). Marine oil supplementation had no effect on the progressive accumulation of cholesterol in the thoracic aorta (28.8 +/- 2.5 mg/gm vs. 29.4 +/- 1.8 mg/gm, group IV vs. group III, p = 0.84). The abdominal aortic cholesterol contents were also similar. These results do not support the use of dietary marine oil supplements for the amelioration of lipid metabolism or the prevention of atherosclerosis.
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PMID:Dietary marine oil supplements fail to affect cholesterol metabolism or inhibit atherosclerosis in rabbits with diet-induced hypercholesterolemia. 276 25

Human atherosclerotic fibrous plaques display a clonal character similar to many benign neoplasms. We report here that chickens treated with an initiation-promotion sequence developed focal intimal smooth muscle lesions in the thoracic aorta that resemble early forms of atherosclerosis. Scanning electron microscopy revealed small mound-like lesions protruding from an intact endothelium in birds treated with an initiating dose of 7,12-dimethylbenz[a]anthracene (Me2BA) followed by twice weekly injections of the alpha 1-selective adrenergic agonist methoxamine for 20 weeks. Intimal lesion foci were composed of densely packed modified smooth muscle cells, abundant extracellular matrix, and occasional mononuclear cells (possibly monocytes). There was no ultrastructural evidence of lipid accumulation or alteration of the underlying media. These intimal lesions appeared in aortic segments of treated chickens in a pattern similar to that observed in classical experiments of multistage tumorigenesis in epidermis and other tissues. The treatment with Me2BA followed by methoxamine produced more focal lesions per thoracic segment and more segments per group with lesions than did treatment with either Me2BA or methoxamine alone. Thoracic intimal foci were absent from untreated and vehicle-treated groups. In contrast, the growth of a spontaneously arising atheroma in the distal abdominal aorta was not demonstrably affected by the initiation-promotion regimen. Likewise, weekly injections of Me2BA for 23 weeks, while greatly enhancing abdominal atheroma growth, produced no thoracic lesions. These results provide evidence that focal proliferation of intimal smooth muscle cells, a critical early event in atherogenesis, can be produced by an initiation-promotion treatment sequence.
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PMID:Focal smooth muscle proliferation in the aortic intima produced by an initiation-promotion sequence. 392 78

Thoracic aortic aneurysms were detected in 72 residents (44 women and 28 men) in a stable midwestern community over a 30-year period, for an age- and sex-adjusted incidence of 5.9 new aneurysms per 100,000 person-years. The incidence was equal in both sexes and decreased slightly over the 30 years. Ages ranged from 47 to 93 years (median 65 years for men and 77 years for women). The ascending aorta was involved in 37 patients, the aortic arch in 8, and the descending aorta in 27. Pathologic examination was performed in 51 patients. The cause was aortic dissection in 27 patients (53%), atherosclerosis in 15 (29%), aortitis in 4 (8%), cystic medial necrosis in 3 (6%), and syphilis in 2 (4%). All autopsied patients had pathologic evidence of significant hypertension. Eleven patients (25%) had concomitant abdominal aortic aneurysms. Rupture occurred in 53 patients (74%) and 50 died. Thirty-seven of these patients had no prior diagnosis of aneurysm. The median interval between diagnosis and rupture in the 16 remaining patients was 2 years (range 1 month to 16 years). Ninety-five percent of aortic dissections ruptured and 51% of nondissecting aneurysms ruptured. The actuarial 5-year survival for all 72 patients was 13%; for patients with aortic dissection, 7% and for patients without dissection, 19.2%.
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PMID:Thoracic aortic aneurysms: a population-based study. 714 88

Arterial influx of esterified cholesterol from 2 plasma lipoprotein fractions, d less than 1.019 and d greater than 1.019, and influx of plasma free cholesterol were determined in each of 15 hypercholesterolemic rabbits with approximately the same plasma cholesterol concentrations but with different extents of arterial lesions. The procedure consisted of injecting intravenously into recipient rabbits [14C]- or [3H]cholesterol-labeled lipoproteins prepared from donor rabbits. The esterified cholesterol of one lipoprotein fraction was labeled primarily with one isotope and that of the other lipoprotein fraction was labeled with the other isotope. Thoracic aortas were removed 4-6 h after lipoprotein injections. The arterial influx of esterified cholesterol was up to 50 times higher in rabbits with maximal lesions than in those with minimal cholesterol deposits. the arterial influx of cholesteryl ester derived from d less than 1.019 lipoproteins was about equal to that derived from the d greater than 1.019 fraction. The amount of cholesteryl ester in plasma d less than 1.019 was approximately 3 times that in d greater than 1.019. Thus, per unit of cholesteryl ester concentration the d less than 1.019 lipoproteins delivered about 1/3 as much cholesteryl ester to the artery as the lipoproteins in the higher density fractions. some 5-40% of plasma esterified cholesterol which had entered the artery was hydrolyzed in the artery during the experimental period. The influx of free cholesterol that could not be accounted for by the influx of intact plasma lipoproteins was 5-80% of the free cholesterol influx. This excess probably represents free cholesterol influx by an exchange between the plasma lipoproteins and the intimal surface of the artery.
Atherosclerosis 1981 Apr
PMID:Arterial influx of esterified cholesterol from two plasma lipoprotein fractions and its hydrolysis in vivo in hypercholesterolemic rabbits. 724 94

To identify the initial period and type of lipid accumulation during spontaneous atherosclerosis, quantitative chromatographic profiles of major lipid classes in upper thoracic aortas (non-lesion areas) and celiac artery cushions (lesion areas) were obtained from atherosclerosis-susceptible White Carneau (WC) and atherosclerosis-resistant Show Racer (SR) pigeons from 1 day to 6 months of age. Thoracic aortas of WC and SR pigeons contained similar amounts of cholesterol, nonesterified fatty acids, triacylglycerols, cholesteryl esters, phospholipids, and hydrocarbon at each age studied. However, celiac sites in WCs contained more total lipid than corresponding SR sites at 6 weeks and 6 months of age. This initial increase at 6 weeks in WCs was characterized by invreased concentrations of nonesterified saturated fatty acids. By 6 months of age, WC celiac cushions had greater concentrations of each lipid class except hydrocarbon than did SR cushions. This initial lipid accumulation was accompanied by ultrastructural changes within the arterial wall, which included the presence of extracellular, vesiclelike structures and extensive accumulation of basal lamina-like material between cells. This material was not present in aortic regions that are not predisposed to lesion formation. This material increased by 6 months of age in the enlarging WC fibromuscular intimal cushions. These morphologic changes paralleled the quantitative lipid increases and represented the first morphologic changes detectable at this site. Age-related changes in arterial lipid content and ultrastructure in SRs are different from those related to early spontaneous atherogenesis in WCs.
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PMID:Lipid accumulation and ultrastructural change within the aortic wall during early spontaneous atherogenesis. 741 36

We delineate the current role of extra-anatomical revascularization techniques in the treatment of patients with atherosclerotic renal artery stenosis. There are 2 components to this study. In part 1 all abdominal aortograms performed between 1989 and 1993 were reviewed to document the presence of significant abdominal aortic and visceral arterial atherosclerosis in patients with atherosclerotic renal artery stenosis. A total of 254 patients with atherosclerotic renal artery stenosis was identified. Among 44 patients with severe unilateral disease the incidence of significant abdominal aortic atherosclerosis was 75%. The incidence of significant (greater than 50%) stenosis of the celiac, right common iliac and left common iliac arteries was 52%, 32% and 27%, respectively. In 129 patients with severe atherosclerotic renal artery stenosis bilaterally or in a solitary kidney the incidence of significant abdominal aortic atherosclerosis was 81%, and the incidence of significant (greater than 50%) stenosis of the celiac, right common iliac and left common iliac arteries was 59%, 57% and 59%, respectively. These data indicate that hepatorenal, splenorenal and iliorenal bypass cannot be performed in many patients with atherosclerotic renal artery stenosis due to significant disease involving the donor vessels for these operations. In part 2, all patients undergoing surgical renal revascularization with an extra-anatomical bypass operation between 1980 and 1992 were reviewed. A total of 175 operations was done in 171 patients, including hepatorenal bypass in 59, splenorenal bypass in 54, iliorenal bypass in 37, thoracic aortorenal bypass in 23, renal autotransplantation in 1 and superior mesentero-renal bypass in 1. There were 5 operative deaths (2.9%) and 7 cases of postoperative graft thrombosis (4%). All patients with poorly controlled hypertension were cured or improved postoperatively. Among patients with ischemic nephropathy, postoperative renal function improved in 35%, remained stable in 47% and deteriorated in 18%. Extra-anatomical techniques remain an important component of the surgical armamentarium for atherosclerotic renal artery stenosis. Thoracic aortorenal bypass is a useful new approach in patients with significant celiac and iliac occlusive disease.
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PMID:The contemporary role of extra-anatomical surgical renal revascularization in patients with atherosclerotic renal artery disease. 775 20

A new technique for renal revascularization has been developed that involves placement of an interposition saphenous vein bypass graft from the lower thoracic aorta to the renal artery. The initial clinical results with this approach have been excellent. Thoracic aortorenal bypass has several advantages and can be useful in the management of selected older patients with severe atherosclerosis of the abdominal aorta and renal arteries.
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PMID:Use of the thoracic aorta for renal revascularization. 817 1


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