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Query: UMLS:C0004153 (atherosclerosis)
 77,401 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Uncomplicated human atherosclerotic plaques often contain large amounts of cholesterol esters and solid cholesterol monohydrate crystals. If such plaques are to regress the crystalline cholesterol would have to dissolve and be transported out of the arterial wall. Since cholesterol is quite insoluble in water, dissolution of plaque crystals might occur through lipids in the plaque, specifically, the cholesterol esters. As part of a study on feasibility of plaque reversal we have studied a specific step involving the dissolution of cholesterol monohydrate into cholesterol ester oil. With specific considerations of the composition and physical state of the cholesterol ester solvent, the size and form of cholesterol monohydrate crystals, the agitation rate, the temperature and the presence of water, we have found that cholesterol esters are an efficient solvent for cholesterol monohydrate crystals. The rate of dissolution was fast reaching 90% of saturation in 1 h. We conclude dissolution of cholesterol monohydrate into cholesterol ester oil is not a rate-limiting step in reversal of the atherosclerotic plaque. We suggest that transport of dissolved cholesterol from cholesterol ester oil may limit the removal. If transport of dissolved cholesterol could be enhanced, cholesterol monohydrate crystals could be rapidly dissolved and facilitate reversal of atherosclerotic lesions.
Atherosclerosis 1978 Jul
PMID:The dissolution of cholesterol monohydrate crystals in atherosclerotic plaque lipids. 67 18

The antioxidation defenses recognized thus far appear too weak. Needed are inert barriers to encapsulate foci of activated oxygen (FAOs) and contain their spreading. These capsules must: 1. self-assemble nonenzymatically and spontaneously in face of adversity; 2. resist oxidation and dissolution in water; and 3. be moderately fluid and elastic enough to withstand flexing by tissues. Evidence shows activated oxygen: a. is produced by common cholesterolester (CE)-raising agents; b. boosts accumulation of CEs; and c. splits low-density lipoproteins (LDL), thus releasing CE-rich coalescence-prone lipid micelles. I am proposing that CEs, combined with polar lipids, are uniquely suited to form inert-lipid antioxidation barriers (ILABs). Porous ILAB capsules self-assemble from lipid micelles released by oxidatively degraded LDL. The capsules are thermodynamically unstable but elastic, durable and capable of self-repair through oxidation of ambient LDL. All capsules tend to contract into spheres. Enclosed needle-like "foreign bodies", such as asbestos, puncture the contracting capsules. Hence the odd bulbous architecture of asbestos bodies. ILABs protect from--and their failure initiates and promotes--carcinogenesis and atherosclerosis. ILABs may be mediators of membrane biogenesis. The loss of arterial flexibility in atherosclerosis protects ILAB capsules from breakage.
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PMID:Biological autoxidation. II. Cholesterol esters as inert barrier antioxidants. Self-assembly of porous membrane sacs. An hypothesis. 74 27

Fourteen normal dogs received continuous infusions of intravenous heparin for one year by means of an implantable infusion pump. Heparin wad admistered at an overall mean rate of 666 units/kg/day, a dose sufficient to prolong the Lee-White clotting time to greater than twice normal. Eight control, animals, under the same dietary and activity regimen, received continuous infusions of bacteriostatic water for one year by means of implanted pumps. Serum cholesterol concentrations rose to 50% above control values after one month of heparin infusion, and remained significantly (P less than 0.05) elevated at this level for the remaining 11 months. Serum triglyceride levels were unchanged. A possible mechanism for this elevation resides in the known effect of heparin to increase plasma free fatty acid concentrations by its activation of lipoprotein lipase. These results may have implications for the long-term use of heparin anticoagulation in the treatment of atherosclerotic states in man.
Atherosclerosis 1977 Jan
PMID:The effect of continuous heparin infusion for one year on serum cholesterol and triglyceride concentrations in the dog. 83 45

The urinary exretion of chromium was studied for relationships to atherosclerotic diseases in two rural Finnish male populations, aged 55 to 74; one from eastern Finland, the other from the southwestern part of the country. A 10-year follow-up had shown a particularly high mortality from coronary heart disease in the eastern area where the concentrations of chromium in the drinking water were lower than in the western area. The 24-hr urinary excretions of chromium of the two populations were markedly low (east, mean +/- SEM, 3.60 +/- 0.15 microgram; west, 3.74 +/- 0.13 microgram), suggesting a suboptimal chromium intake in both populations. No consistent differences were found in urinary chromium excretions between groups with atherosclerotic diseases and reference groups. The role of low chromium intake in the pathogenesis of atherosclerosis deserves further study.
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PMID:Urinary chromium excretion and atherosclerotic manifestations in two Finnish male populations. 88 61

Chromium is an essential trace element in mammals since dietary chromium deficiency results in glucose intolerance due to decreased sensitivity to insulin. In humans, both adults and children with glucose intolerance have been improved by treatment with chromium. Furthermore, chromium deficiency has been implicated as a causative factor in hypercholesterolemia and atherosclerosis. However, little is known of the metabolism of chromium in humans, primarily because of analytical difficulties. The biologically active form of chromium is the "glucose tolerance factor" (GTF) which is a co-ordination complex of trivalent chromium with nicotinic acid and certain amino acids. At physiological pH, ionic chromium as a simple inorganic salt is insoluble in water, but trivalent chromium forms stable complexes with ascorbic acid, amino acids and other substances present in blood and tissue. Chromium is present in serum, bound to protein and also as dialysable or ultrafiltrable chromium (free chromium). The free chromium includes G.T.F. and other coordination complexes and represents the metabolically active form of the element; the ratio free/protein bound chromium in serum varies within the individual according to the diet and the metabolic state.
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PMID:The measurement of volatile chromium in biological materials. 91 55

The water flux through preparations of porcine aorta has been investigated. After an initial unsteady period a stable flux of approximately 2 mul/cm2-h was reached and this flux rate remained constant for several hours. Under the experimental conditions which were maintained (110 mm Hg pressure drop across a 2 mm thick section of tissue) this total flux corresponds to a hydraulic conductivity of less than or equal to 7.0 X 10(-13) cm4/dyne-sec. Since these data were obtained in tissue samples where the endothelial layer was not intact, they represent values which are in fact larger than the actual in vivo condition where the endothelial barrier would serve as an additional resistance. Thus, they demonstrate that the transmural flux of water across the aorta wall in vitro due to a pressure gradient is extremely small and, therefore, that other mass transfer mechanisms may be significant.
Atherosclerosis 1976 Sep
PMID:Water flux through porcine aortic tissue due to a hydrostatic pressure gradient. 97 39

It has been suggested that the glycosaminoglycans (GAG) influence atherogenesis by regulating the permeability of the arterial wall. For this reason, a study has been made of the diffusive transport of Ca2+ and water across the in vitro porcine artery wall, where particular attention was focused on the influence of GAG content and distribution within the wall on the transport properties. The radioisotop-s 45Ca and 3HHO were used to measure the tracer-diffusion flux in a stirred, two chamber diffusion cell. GAG were isolated, fractionated using a cetyl pyridinium chloride-cellulose column procedure, and assayed using a colorimetric carbazole reaction for uronic acid. The biochemical analyses showed that the pulmonary artery contains significantly more hyaluronic acid and dermatan sulfate than found in two locations in the thoracic aorta. In addition, a significant regression was found for the diffusion coefficient of 45Ca2+ (99% level) and 3HHO (95% level) versus specific GAG fractions. The regression indicated an increase in permeability with increase in the ratio of sulfated: nonsulfated GAG.
Atherosclerosis
PMID:Influence of glycosaminoglycan content on mass transfer behavior of porcine artery wall. Part 2. Differences in mass transfer rates related to variations in glycosaminoglycan content. 100 5

The diffusion coefficients of Ca2+ and H2O in in vitro porcine arterial tissue were determined to provide a measure of vascular permeability. The effect of anatomical location and diet on the magnitude of that permeability was evaluated. The diffusion coefficient of calcium was found to vary focally and, in addition, pulmonary artery was much more permeable than thoracic aorta. Four months feeding of a high lipid diet did not affect diffusive transport.
Atherosclerosis
PMID:Influence of glycosaminoglycan content of mass transfer behavior of porcine artery wall. Part 1. Diffusive transport of 45Ca2+ and 3HHO. 100 4

In Rhesus monkeys, nicotinic acid given daily by subcutaneous injection for 5 weeks brought about a reversible decrease in total cholesterol concentration in skeletal muscle and skin to about half the normal value. The decrease in cholesterol concentration was due to a net loss of cholesterol from muscle, since the treatment had no effect on the water content or on the percentage of DNA or protein in fresh tissue. In muscle, free cholesterol was lost in preference to esterified cholesteol, but in skin both cholesterol fraction were affected to about the same extent. Analysis of the cholesterol content of subcellular fractions of homogenates of muscle showed that loss of cholesterol occurred mainly from the soluble fraction and the 800-g sediment, with no significant loss from the mitochondrial or microsomal fractions.
Atherosclerosis
PMID:Loss of cholesterol from muscle and skin of monkeys treated with nicotinic acid. 113 7

The selectively-bred substrains of spontaneously hypertensive rats with a greater vulnerability to vascular lesions rapidly developed arterial fat deposition within 1 or 2 weeks as well as a greater hypercholesterolemic response when fed on high fat cholesterol diet including 20% of suet, 5% of cholesterol and 2% of cholic acid. The ring-like arterial fat deposition at the branches of superior mesenteric arteries and cerebrobasal arteries, which was found to be good indices for the deposition of intrarenal or coronary arteries, was not observed in normotensive rats fed on high fat cholesterol diet for 3 months, greatly delayed in SHR under antihypertensive treatment and accelerated by 1% salt loading in drinking water. The horseradish peroxidase infused intravenously 1 to 4 hours before sacrifice leaked in ring-like forms which corresponded to the fat deposit in mesenteric arteries. The incorporation of 3H-proline infused 4 hours before sacrifice was enhanced in the mesenteric arteries with the fat deposition. These results clearly indicated that hypertension was a great contributory factor to rapid arterial fat deposition, which was caused by an increased vascular permeability and enhanced the arterial collagen formation, the initiation process of arterio- or atherosclerosis.
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PMID:Pathogenesis of acute arterial fat deposition in spontaneously hypertensive rats. 115 92


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