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PubMed1977

Renal revascularization in patients with severe atherosclerosis of the abdominal aorta or a previous operation on the abdominal aorta.

Renal revascularization has been performed in six patients in whom severe atherosclerosis or previous operative procedures on the abdominal aorta precluded the performance of a standard aortorenal bypass graft. Splenorenal anastomoses were performed in three patients, superior mesenterorenal anastomosis in one patient, long saphenous vein iliorenal anastomosis in one patient, and renal autotransplantation in one patient. Successful renal revascularization with preservation of renal function was accomplished in all patients. The natural history of severe atherosclerotic renovascular disease has demonstrated the relatively frequent occurrence of arterial thrombosis and renal failure in patients with solitary kidneys. Occasionally, the presence of severe aortic disease precludes the use of standard aortorenal bypass grafting. Fortunately, as reported herein, alternate methods of revascularization are available whereby renovascular hypertension can be corrected and renal function preserved, with minimal operative risk.

Adult↗
PubMed1977

Injury to ascending aorta by partial-occlusion clamp during aorta-coronary bypass.

Disease of the proximal ascending aortic wall from prolonged, poorly controlled hypertension predisposed to intimal injury after clamp compression. This creates a spectrum of problems: (1) intimal tear with late formation of a localized aneurysm, (2) delayed acute dissecting aneurysm, and (3) intraoperative acute dissecting aneurysm. Principles of management are discussed.

Aged↗
PubMed1977

Pathogenesis of dissecting aneurysm of aorta. Comparative histopathologic study of significance of medial changes.

In previous investigation of the normal aging aorta, the claimed specificity of alterations in the media in the pathogenesis of dissecting aneurysm of the aorta was challenged. The concept was promoted that these changes are nonspecific and caused by general hemodynamic events within the aorta. In this investigation the aortic media was studied in patients with a dilated ascending aorta, whose hemodynamic profile is known to be altered. The results were compared with data obtained from the study of aortas with complete or incomplete dissection and aortas from patients with Marfan's syndrome, a condition known to predispose to dissection. Only quantitative differences were found between the normal "aging" aorta and the overtly abnormal aorta. The pathogenesis of dissected aneurysm, therefore, is considered to be initiated by processes if injury and repair within the aortic wall, consequent to hemodynamic forces. The histologic features of the media previously implicated as the specific underlying defect appear to represent the morphologic substrate of this traumatizing and reparative process. This process may gradually lead to dilatation of the aorta and, according to Laplace's law, a vicious cycle may ensue that may lead to further complications. Local circumstances determine whether a dilated aorta will rupture or whether an incomplete or complete dissection will occur. The fact that the aorta in patients with Marfan's syndrome shows basically the same structural alterations supports the concept proposed. The underlying connective tissue disorder in these patients will lead to complications at an earlier age. Dissecting aneurysm therefore is part of a spectrum of lesions that have as a common denominator the process of injury and repair.

Adolescent↗
PubMed1979

Uptake and esterification of circulating carnitine by aorta and heart in rabbits in vivo.

Disappearance of intravenously injected DL-[methyl-14C]carnitine from the bloodstream and its uptake and esterification by heart and aorta were studied in rabbits fed atherogenic or non-atherogenic control diets. The disappearance rate of [14C]carnitine from the bloodstream was approximately 2-fold greater in animals fed the control diet than in those fed the atherogenic diets. No evidence was found for carnitine esterification in the blood. Circulating [14C]carnitine was taken up and esterified in both the heart and aorta of all animals regardless of diet; however, on comparing dpm/mg lipid-free dry weight, uptake of [14C]carnitine and accumulation of [14C]carnitine esters by the heart was greater (6-fold and 12-fold, respectively) than by the aorta. Analysis of defined arterial segments indicated that aortas in animals fed the atherogenic diet contained greater [14C]carnitine activity (4- to 8-fold) and greater acetyl-[14C]carnitine activity (4-fold) when compared to aortas of control animals; uptake of plasma [14C]carnitine and accumulation of acyl-[14C]carnitine compounds by the heart was independent of diet. Butyryl-[14C]carnitine, although not detected in aortas from animals fed the non-atherogenic or atherogenic diet for only 7 weeks, was detected in aortas from animals fed the atherogenic diet 17 weeks. Butyryl-[14C]carnitine was detected in heart tissue regardless of the animals' dietary regime. The increased uptake of circulating [14C]carnitine and its accumulation as both free and esterfied carnitine in atherosclerotic aortas occurred before the development of extensive macroscopic atherosclerotic lesions; this response of the aorta to atherogenic stimuli was not a general tissue response in that the heart did not respond similarly. Since blood carnitine is found predominantly in the plasma fraction, it is likely that these results refect the uptake and metabolism of plasma carnitine in vivo.

Animals↗
PubMed1979

Surgery of the ascending aorta: five years' experience at a regional cardiac centre.

Between 1972 and 1978, 31 patients underwent replacement of the ascending aorta, with or without aortic valve surgery, at the Wessex Regional Cardiac Centre. The commonest indications for operation were aneurysmal dilatation of the ascending aorta causing aortic regurgitation and acute dissection of the ascending aorta. Eleven of the 31 patients had features of Marfan's syndrome. The overall hospital mortality was 19.4%, a figure comparable with those reported in other series; ventricular failure secondary to ischaemia during operation was the commonest cause of death. The long-term symptomatic results were excellent, except in the two patients who underwent resuspension of the aortic valve for aortic regurgiation associated with acute dissections. For aneurysms of the ascending aorta with associated aortic regurgitation, replacement of the valve and ascending aorta with a combined valve prosthesis and synthetic tube graft, with reimplantation of the coronary ostia, is the procedure of choice if the aortic valve ring is diseased. Experience to date indicates that replacement of the ascending aorta and aortic valve with separate prostheses, leaving the coronary ostia undisturbed, is a satisfactory alternative provided the aortic annulus is of suitable size and quality; this is more likely to be the case in dissections than in aneurysmal dilatation of the ascending aorta. Replacement of the ascending aorta may also be indicated in some cases of dilatation of the ascending aorta secondary to aortic valve disease if the aortic wall is unusually thin.

Adult↗
PubMed1977

The role of prostaglandins in hypertension. I. The release of prostaglandins by aorta strips of renal, DOCA-salt, and spontaneously hypertensive rats.

The release of prostaglandin-like (PG-like) material by aorta strips of normotensive and hypertensive rats has been studied in vitro. When incubated in an oxygenated Krebs solution kept at 37 degrees C, aorta strips removed from 8- and 12-week-old spontaneously hypertensive (SH) rats generate 1.2-2.5 times more PG-like material than aorta strips from age-matched normotensive Wistar (NW) rats. The overproduction of PG-like material by aorta strips of SH rats did not precede the development of hypertension in SH rats. Aorta strips derived from renal and DOCA-salt hypertensive rats produced 1.5-3 times more PG-like material than aorta strips from NW rats. The production of PG-like material by aorta strips of renal and DOCA-salt hypertensive rats was largely reduced when hypertension was interrupted in these animals, thus suggesting that the alteration taking place in the arteries of hypertensive rats (namely increased production of PGs) during the development of hypertension was reversible. The production of PG-like material by aorta strips of hypertensive rats was inhibited by indomethacin. Analysis of the PG-like material by bioassays and thin-layer chromatography suggests the presence of PGE2 and PGE1. The possible involvement of these PGs in the pathogenesis of hypertension in rats is discussed.

Animals↗
PubMed1978

Use of a ringed intraluminal graft in the surgical treatment of dissecting aneurysms of the thoracic aorta. A new technique.

An intraluminal graft made of woven tubular Dacron with cloth-covered grooved rings at both ends is used to repair dissecting aneurysms of the thoracic aorta. Six consecutive white male patients ranging in age from 31 to 69 years with an average age of 55 years were operated upon with the use of this graft. Three patients had a dissecting aneurysm of the ascending aorta and three others had a dissecting aneurysm of the descending aorta. Total cardiopulmonary bypass was utilized in repairing dissecting aneurysms of the ascending aorta and left heart bypass was used in patients with dissecting aneurymsms of the descending aorta. The basic technique consists in inserting the whole ringed graft into the true lumen of the dissected aorta and circumferentially ligating the aorta against the groove in the rings. The proximal ring of the graft effectively stabilized the flail aortic valve in two patients with aortic regurgitation associated with dissection of the ascending aorta. There were no hospital deaths. All patients are doing well 1 year, 1 month to 2 years, 8 months after the operation.

Adult↗
PubMed1978

[Segmental replacement of thoracic aorta with autologous pericardium during growth (author's transl)].

Surgical treatment of coarctation of the aorta in the newborn often recurs during childhood. As a means of avoiding this complication segmental replacement of the thoracic aorta with autologous pericardium was evaluated. The isthmic aorta of seven mongrel puppies was replaced by a tubular live pericardial autograft. Between 5 and 36 months (average 15) after surgery, the status of the graft was evaluated by hemodynamic, angiographic, macroscopical and histological studies. Growth of the graft was appreciated by comparing its diameter to that of the descending aorta DG/DA. No pressure gradient across the graft was noted. No significant structure of the graft was observed. The internal surface of the graft was smooth, and the wall, slightly thinner than that of the aorta showed no aneurysm. The diameter of the graft was increased (DG mean 37 %) proportionally to the increase of the aorta (DA mean 36 %). Histologically the graft was endothelialized, the wall was thickened and made up of concentric collagen fibers, live fibroblasts and muscular cells. These results show that during the first months of life, the isthmus of the aorta can be replaced by an autologous pericardial graft which will follow the growth of the normal aorta and adapt to its hemodynamic regimen.

Animals↗
PubMed1978

Prostaglandin E2 biosynthesis and effect in pigeon aorta. Possible role in atherogenesis.

This study for the first time examines the biosynthesis and effect of prostaglandin E2 (PGE2) in aorta during genetic atherosclerosis. Biosynthesis of PGE2 from [1-14C]arachidonic acid was investigated in the aorta of spontaneously atherosclerosis-susceptible White Carneau pigeons and was compared with that of the atherosclerosis-resistant Show Racer breed. Most of the PGE2 synthetase activity was located in the microsomes. The synthesis was linear up to an hour and was optimal at pH 7.4. The formation of PGE2 in the aorta in the White Carneau pigeons was significantly higher (P less than 0.01) than that in age-matched Show Racer pigeons. In vitro PGE2 strongly inhibited the cholesteryl ester hydrolase activity (51.6% inhibition at 4 X 10(-7) M concentration) in the supernatant fraction of the aorta. On the basis of (1) the increased formation of PGE2 in the aorta of atherosclerosis-susceptible pigeons and (2) its effect on specific enzymes that control cholesteryl ester concentration in aorta, it is hypothesized that PGE2 synthesized at a higher rate in damaged aorta has a significant role in cholesteryl ester accumulation during atherogenesis.

Animals↗
PubMed1976

Receptors for 5-hydroxytryptamine and noradrenaline in rabbit isolated ear artery and aorta.

5-Hydroxytryptamine (5-HT) is thought to be implicated in the vascular disturbances of the external carotid artery bed associated with migraine. As part of a study of the pharmacology of some 5-HT antagonists used in the treatment of migraine we have examined the interactions of these drugs with 5-HT and noradrenaline in rabbit isolated ear artery and aortic strip. The results provide new information on the distribution of 5-HT-receptors in these preparations. In the aorta, 5-HT and noradrenaline were of similar potency in producing contractions. Methysergide produced very small contractions and was about 1000 times less potent than the other two agonists. In the ear artery noradrenaline produced monophasic vasoconstrictor responses, whereas 5-HT and methysergide produced prolonged biphasic responses. 5-HT was about 700 times less potent and methysergide about 4500 times less potent than noradrenaline. Methysergide was a better agonist in the ear artery than in the aorta. Biphasic responses to 5-HT and methysergide were also obtained in ear arteries from reserpine-treated rabbits indicating that neither agonist was acting by releasing endogenous noradrenaline. Pizotifen, cyproheptadine and phentolamine had no agonistic actions in either the aorta or ear artery. In the aorta methysergide, pizotifen and cyproheptadine were potent antagonists of 5-HT and much weaker antagonists of noradrenaline. Phentolamine possessed the opposite profile of selectivity. These results show that there are distinct receptors for 5-HT and noradrenaline in rabbit aorta. In the ear artery the pA2 values for each of the four antagonists were virtually identical against 5-HT and noradrenaline and similar to those obtained on alpha-adrenoceptors in the aorta. We conclude that 5-HT and noradrenaline act directly at alpha-receptors to produce vasoconstriction in the ear artery and that this preparation does not contain specific 5-HT receptors. This insight into the distribution of 5-HT receptors and alpha-receptors allows interpretation of the various actions of methysergide. In the aorta, methysergide was a potent antagonist at 5-HT-receptors and a weak partial agonist at alpha-receptors. In the ear artery, methysergide was a partial agonist at alpha-receptors; it was only a weak antagonist of 5-HT because this preparation does not contain specific 5-HT-receptors. The cross-reactivity demonstrated throughout these experiments indicates that 5-HT-receptors and alpha-receptors, although distinct entities, have features in common. These results are discussed in relation to the mode of action of methysergide, pizotifen and cyproheptadine in the treatment of migraine.

Animals↗
PubMed1979

[Early detection and observation of the evolution of congenital malformations of the aorta in newborn infants, infants and young children].

UNLABELLED: 57 infants and small children (42 boys and 15 girls) with congenital aortic malformations were investigated. Clinical, ecg and X-ray follow-up was carried out. Following 4 groups of patients were separated: 1) neonates and infants with supraductal (preductal) aortic hypoplasia or atresia, with hypoplastic left ventricle of the heart (5 boys and 2 girls), 2) infants with supraductal coarctation of the aorta, without underdevelopment of the left heart cavities (2 boys and 2 girls), 3) infants and children with postductal coarctation of the aorta (17 boys and 3 girls) and 4) infants and children with valvular or/and subvalvular, or supravalvular aortic stenosis (18 boys and 8 girls). CONCLUSIONS: Congenital malformations of the aorta and of the left side of the heart should be suspected in all neonates and infants displaying early symptoms of cardiorespiratory failure, resembling frequently the symptoms of severe "pneumonia". Proper measurement and thorough analysis of arterial pulses and pressures in upper and lower extremities is of great importance in detection and differential diagnosis of congenital aortic malformations in infants, even when features of other cardiovascular lesions (e.g. ventricular septal defect, endocardial cushion defect, transposition of the great arteries) dominated in the clinical picture of complex malformations. Small amplitudes of peripheral arterial pulses, with considerably--prolonged upstroke time, small amplitude of arterial pressure measured in upper and lower extremities, co-existing with electrocardiographic patterns of the right ventricular hypertrophy--suggested an aortic malformation complicated by hypoplasia of the left ventricle. Distinctly lower systolic and mean arterial pressure in legs, than in arms was typical for coarctation of the aorta. Significant differences in diastolic pressure values in arms and legs with coexisting ecg patterns of dominating right ventricular hypertrophy should rise a suspicion of abnormal, separate communication of the ascending aorta, and the descending aorta, separately from the left and from the right ventricles of the heart. The electrocardiogram seems to be of great help in differentiation between aortic lesions with or without hypoplastic left ventricle, those with or without systemic right and left ventricle, and those with systemic left ventricle only. Early detection, diagnosis, prompt and proper medical and surgical treatment may be lifesaving for the majority of infants with congenital malformations of the aorta not complicated by left ventricular hypoplasia.

Age Factors↗
PubMed1977

The dietary regulation of stearyl coenzyme A desaturase activity and membrane fluidity in the rat aorta.

Numerous studies have demonstrated that alterations in membrane composition or fluidity are often associated with alterations in the properties of membrane-bound enzymes. In order to obtain membranes of varying fluidity, rats were fed diets that were either fat-free or supplemented with 15% safflower oil, and two properties associated with aorta and liver microsomal membranes were selected for study: stearyl CoA desaturase activity, and fluidity as monitored by fatty acid composition and microviscosity (measured by fluorescence depolarization). If fluidity directly modulates desaturase activity, one would predict that a low fluidity would stimulate the desaturase activity. Ten times more desaturase activity is present in aorta microsomes from rats on a fat-free diet than in microsomes from rats on a safflower oil supplemented diet. However, on the fat-free diet, these aorta microsomes were more fluid than those of rats fed safflower oil supplemented diet. The fluidity of liver microsomal membranes was not altered in response to diet, despite significant changes in desaturase enzyme content. The contrasting evidence presented here suggests that no correlation exists between desaturase enzyme activity and membrane fluidity in the two tissues studies. We have demonstrated that the aorta has appreciable capacity to desaturate stearyl CoA and that dietary manipulation causes significant changes in aorta membrane fluidity that may be of sufficient magnitude to affect the overall metaboism of aorta cells.

Animals↗
PubMed1977

Possible role of endogenous catecholamines in the contractions induced in rabbit aorta by ouabain, sodium depletion and potassium depletion.

Effects of ouabain, Na+ depletion and K+ depletion on the tension development of rabbit aorta were studied. Contraction in the strips was induced by ouabain and Na+-free solution substituted with Li+, tris or sucrose. The contractions were rarely seen under alpha-adrenergic blockade, in reserpinized aorta and mechanically denervated aorta. Contractions induced by norepinephrine were potentiated by Na+ depletion, K+ depletion and ouabain. Contractions induced by high K+ solution were also potentiated by Na+ depletion and ouabain. The potentiation in Li+ solution, K+-free solution and with ouabain was not seen under alpha-adrenergic blockade, in reserpinized aorta and denervated aorta although the potentiation by tris and sucrose solutions was still observed. These data suggest that Na+ depletion, K+ depletion and ouabain release endogenous catecholamines which affect the contraction of the vascular smooth muscle of rabbit aorta.

Animals↗
PubMed1977

Metabolic intermediates, enzymes and lysosomal activity in aortas of spontaneously hypertensive rats.

Metabolic intermediate levels, glycolytic and Krebs cycle enzyme activities and lysosomal acid hydrolase activities were measured in aortas of spontaneously hypertensive (SHR) versus normotensive (WKY) rats. In the hypertensive aortas the level of lactate, the ratio of lactate to glucose and of lactate to malate was higher in the SHR than WKY aortas. In the hypertensive aortas the obvious shift of metabolism toward higher rate of glycolysis was associated with decreased activity of malate dehydrogenase and espically of lipoamide dehydrogenase. The latter is an essential compoenent of the alpha-ketoglutarate and pyruvate dehydrogenase enzyme complexes and it appears that these complexes are among the sites of arterialmetavolism which are primarily altered by the elevated blood pressure, resulting in increased production of lactate. The activity of the marker lysosomal enzyme N-acetyl-beta-glucosaminidase was unequivocally elevated in the hypertensive aortas. The activity of beta-glucuronidase exhibited incogruous differences between the SHR and WKY aortas and the activity of aortic acid phosphatase did not differ in the two rat strains. The results are discussed in relation to arterial injury, permeability, and atherogenesis.

Acetylglucosaminidase↗