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

The structural interaction of egg lysolecithin, derived from egg lecithin, and cholesterol in aqueous solution has been investigated using X-ray diffraction. When mixed in any proportions, either suspended in excess buffer or up to 85% lipid by dry weight, a separate lamellar phase containing equimolar proportions of lysolecithin and cholesterol forms, separate from excess water, or lysolecithin or cholesterol. The cholesterol disorders the crystalline chains of the lysolecithin. The equimolar phase is stable up to 50 degrees C unlike lysolecithin alone, which forms micelles, Thes results show that lysolecithin and cholesterol combine stoichiometrically in a stable complex. We propose as a structural model, that cholesterol fills the space of the missing fatty acyl chain making the lysolecithin more cylindrical rather than wedge shaped. This interaction could reduce both the lytic action of lysolecithin on membranes and its induction of cell fusion. It suggest another role of cholesterol in cell membranes: namely, to act as a stabilizer of bilayer structure by being a mobile component that can fill free volume in the hydrocarbon interior. Lysolecithin-cholesterol interaction may also be important in the early events of atherosclerosis where lysolecithin levels in vessel walls increase fivefold.
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PMID:Lysolecithin and cholesterol interact stoichiometrically forming bimolecular lamellar structures in the presence of excess water, of lysolecithin or cholesterol. 116 27

Theoretical grounds are presented for some methods (administration of isotope and time of sacrifying the animal, estimation of radioactivity in ther material examined, and mathematical processing of the data obtained) with which radioactive water is used as a universal precursor for the study of the integral rates of metabolism in various organs and biochemical components of the body. An analysis of the dynamics of tritium inclusion into the water of the blood and urine of the control animals and of those with experimentally induced atherosclerosis permitted to establish that the development of hypercholesterinemia is accompanied by a decrase (by 26%) of the rate of autorenuewal of the water phase of the macroorganism, one of its causes consisting in an enhanced hydrophility of the tissues in cases of this pathology. A monthly periodicity was noted in the changes of the tritium concentration in the body waters of rabbits, as well as its correlation with the periodical changes in the concentration of serum cholesterol during the development of experimental atherosclerosis. It is suggested that the water and cholesterol metabolism have a joint centralized regulation in the body which essence consists in maintaining the rhythm of each separate kind of metabolism for its synchronization with the other kinds of metabolism in unfavourable outer and inner situations for the macroorganism.
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PMID:[Use of tritium oxide for the study of metabolism during development of experimental arteriosclerosis]. 124 2

The effect of LPSw (a lipopolysaccharide from wheat flour) on cholesterol catabolism was examined using WHHL (Watanabe heritable hyperlipidemic) rabbit, which is an experimental model of familial hyperlipidemia. The serum cholesterol level of the animal decreased by the addition of LPSw to drinking water. Following cessation of the addition of LPSw to the drinking water, the cholesterol level was decreased for 30 to 40d and then gradually elevated. The serum level of apolipoprotein B, which is a constituent of apolipoprotein of low density lipoprotein (LDL), also decreased in accord with serum cholesterol at a nearly coincident rate. Conversely, the level of apolipoprotein A-I, which is a constituent of apolipoprotein of high density lipoprotein (HDL), did not change, nor did HDL-cholesterol. Furthermore, the atherosclerosis risk factor, expressed as the ratio of apolipoprotein B to apolipoprotein A-I, was decreased by LPSw administration.
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PMID:Homeostasis as regulated by activated macrophage. VII. Suppression of serum cholesterol level by LPSw (a lipopolysaccharide from wheat flour) in WHHL (Watanabe heritable hyperlipidemic) rabbit. 139 46

Repeated endothelial cell injury has been suggested as an initiating factor in atherogenesis. Dying or dead endothelial cells have been shown to make significant contributions to the local enhancement of transendothelial macromolecular transport. Since cigarette smoking is one of the major risk factors for atherosclerosis, we examined the hypothesis that smoking accelerates atherogenesis by increasing the frequency of endothelial cell death and hence transendothelial macromolecular transport. Sixteen male Sprague-Dawley rats were given nicotine at a weight-adjusted dose of 5 mg/kg body wt per day in their drinking water over a period of 6 weeks. A group of 16 age-matched male Sprague-Dawley rats not exposed to nicotine and maintained over the same time period served as the control group. In en face preparations of thoracic aorta, immunoglobulin G-containing dying or dead endothelial cells were identified by the indirect immunoperoxidase method, and endothelial leakage to Evans blue-albumin (EBA) complexes (5 minutes after intravenous injection) was visualized by fluorescence microscopy. The results showed that in nicotine-treated rats, 51% of dead endothelial cells were associated with EBA leakage, which was responsible for 57% of total EBA leaky foci. Both the frequency of endothelial cell death (0.94 +/- 0.11% versus 0.40 +/- 0.04%, p < 0.0001 by two-tailed, unpaired Student's t test) and the number density of EBA leaky foci (6.45 +/- 1.23/mm2 versus 3.30 +/- 0.49/mm2, p < 0.05 by two-tailed, unpaired t test) were significantly greater in nicotine-treated rats than in control rats.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Long-term nicotine exposure increases aortic endothelial cell death and enhances transendothelial macromolecular transport in rats. 142 90

The purpose of this study was to determine if chronic administration of L-arginine, the precursor of endothelium-derived relaxing factor (EDRF), normalizes endothelium-dependent relaxation and decreases atherosclerosis in hypercholesterolemic animals. Male rabbits were fed (a) normal rabbit chow; (b) 1% cholesterol diet; or (c) 1% cholesterol diet supplemented by 2.25% L-arginine HCl in drinking water. Arginine supplementation doubled plasma arginine levels without affecting serum cholesterol values. After 10 wk, the thoracic aorta was harvested for studies of vascular reactivity and histomorphometry. Endothelium-dependent relaxations (to acetylcholine and calcium ionophore A23187) were significantly impaired in thoracic aortae from animals fed a 1% cholesterol diet. By contrast, vessels from hypercholesterolemic animals receiving L-arginine supplementation exhibited significantly improved endothelium-dependent relaxations. Responses to norepinephrine or nitroglycerin were not affected by either dietary intervention. Histomorphometric analysis revealed a reduction in lesion surface area and intimal thickness in thoracic aortae from arginine-supplemented animals compared to those from untreated hypercholesterolemic rabbits. This is the first study to demonstrate that supplementation of dietary L-arginine, the EDRF precursor, improves endothelium-dependent vasorelaxation. More importantly, we have shown that this improvement in EDRF activity is associated with a reduction in atherogenesis.
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PMID:Antiatherogenic effects of L-arginine in the hypercholesterolemic rabbit. 152 25

1. The effects of D-fenfluramine were studied in the JCR:LA-corpulent rat that is grossly obese, hyperphagic, hyperlipidaemic, hyperinsulinaemic and atherosclerosis-prone. 2. Daily doses of 1, 2.5 and 5 mg kg-1 of D-fenfluramine produced sustained decreases in body weight and food intake over a period of 30 days in 6 month old female rats fed ad libitum. This was accompanied by decreases in the circulating concentrations of glucose, triacylglycerol, free cholesterol and insulin. 3. Food restriction imposed by meal feeding also decreased circulating glucose, triacylglycerols, cholesterol and insulin and diminished the effect of D-fenfluramine on these parameters in male and female rats. 4. Addition of D-fenfluramine to drinking water to give a dose of about 0.25 mg kg-1 daily produced a sustained decrease in body weight and food intake of male and female rats over a nine week period. 5. The results show that the JCR:LA-corpulent rat is very sensitive to the pharmacological effects of D-fenfluramine. These rats should provide an appropriate animal model for determining the mechanisms of action of this anti-obesity agent and whether apparently beneficial changes in metabolism translate into long-term protection against premature atherosclerosis.
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PMID:Sustained decreases in weight and serum insulin, glucose, triacylglycerol and cholesterol in JCR:LA-corpulent rats treated with D-fenfluramine. 162 54

Adding less than 0.5% w/w of culture material of strain MRC 826 of the fungus Fusarium moniliforme to a carbohydrate diet low in fat resulted in an atherogenic plasma lipid profile in a non-human primate. Simultaneously increased plasma fibrinogen and activity of blood coagulation factor VII could enhance atherogenesis. This unique potential for promotion of atherosclerosis was probably secondary to chronic hepatotoxicity as indicated by liver fibrosis and elevated cholesterol, albumin and the enzymes AST, ALT, LD, GGT and ALP in serum. The cholesterol and enzymes responded in proportion to the calculated doses of fumonisin mycotoxins in the F. moniliforme MRC 826 cultures. Fumonisins are water soluble and heat stable. Thrombotic, hepatotoxic, carcinogenic and cerebral effects of MRC 826 culture material and fumonisins are well known in non-primates. The estimated fumonisin concentrations tested fall within a range due to natural contamination of human foods. The results suggest that all maize grain products should be analysed for fumonisins.
Atherosclerosis 1992 May
PMID:Atherogenic effects in a non-human primate of Fusarium moniliforme cultures added to a carbohydrate diet. 163 55

A proteinase-inhibitory balance of blood (elastase-like activity, alpha 1-proteinase inhibitor and alpha 2-macroglobulin activities) was studied in practically healthy inhabitants of the Chuvash ASSR two subregions--Sura river basin and Cubninocivil region, which are distinctly dissimilar in all the biogeochemical parameters involving macro- and microtrace compositions. The higher activity of elastase-like proteinases and decreased content of alpha 1-proteinase inhibitor were detected in practically healthy inhabitants of the river Sura basin, where high incidence of myocardial infarction was found, as compared with those of the Cubninocivil people. The similar alterations in the proteinase-inhibitory balance were observed in blood of experimental animals maintained on a diet containing fresh water from these subregions. The data obtained suggest that there exists causative relationship between biogeochemical parameters and development of imbalance in the proteinase-inhibitor system in practically healthy inhabitants of the river Sura basin. This imbalance is considered as a pathogenetic factor responsible for development of atherosclerosis.
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PMID:[Activity of elastase-like proteinases and their inhibitors in indigent nearly healthy residents in various biogeochemical conditions of the Chuvash ASSR]. 172 75

This review article attempts to present an overview of the occurrence and function of lipid storage and secretory organelles: the lamellar bodies. Morphologically these organelles vary considerably in size (100 nm to 2400 nm); they are surrounded by a membrane and contain multilamellar lipid membranes. Lamellar bodies may also contain apolipoproteins and lytic enzymes and have an acidic pH, which confers on them a lysosomal character. Under normal physiological conditions, the main function of lamellar bodies is the supply of extracellular domains with specialized lipid components related to a specialized function. The lamellar bodies of the lung epithelium are best investigated in their functional and structural features and are the storage form of the lung surfactant. They provide a monomolecular lipid film of dipalmitoyl phosphatidylcholine (DPPC) on the surface of lung alveoli to lower surface tension necessary for optimal gas exchange and a hydrophobic protective lining against environmental influences. Additional cells of the respiratory system such as the mucosa of the human nose and the bronchi contain lamellar bodies. Lamellar bodies are also found in the gastrointestinal tract, in tongue papillae, oral epithelium, and mucosa cells of the stomach. The major phospholipid of lamellar bodies in mucosa cells of the stomach is DPPC, providing a hydrophobic protective lipid film against the tissue-damaging activities of gastric juice. The hydrophobic water-protective barrier of the skin, which consists mainly of neutral lipids, however, also originates from lamellar bodies secreted by epithelial cells. Lamellar bodies, mainly consisting of DPPC, also occur in mesodermal cell layers of sliding surfaces to provide the lubrication of joints, of the peritoneum, pericardium, and pleural mesothelium. In certain pathological conditions, such as atherosclerosis, Niemann-Pick disease, lecithin:cholesterol acyltransferase (LCAT) deficiency, cholestasis, degeneration of nerves and brain, and regeneration of nerves and wound healing, lipid-containing lamellar bodies have been observed in various cells, the function of which still remains to be elucidated. In early and late lesions of atherosclerotic plaques, lamellar bodies, consisting of unesterified cholesterol and phospholipids, are associated with the extracellular matrix of the intima. During regression of fatty streaks, lamellar bodies are seen intracellularly in macrophages and smooth muscle cells. Inherited metabolic disorders, such as Niemann-Pick disease type I and type II, result in the excessive accumulation of lamellar body-containing cells, for example in bone marrow, spleen, and lymphoid tissue. Type I is a deficiency in sphingomyelinase and type II is a defect in intracellular trafficking of lipoprotein-derived cholesterol.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Structure and function of lamellar bodies, lipid-protein complexes involved in storage and secretion of cellular lipids. 179 38

The known effects of trivalent chromium (Cr) in lowering blood levels of low density lipoproteins (LDL), raising high density lipoproteins (HDL) and improving glucose tolerance are summarised. Chromium deficiency cannot easily be established by direct means, but can be inferred by the reversal of symptoms and signs following the administration of trivalent chromium. This evidence can be supported by knowledge or suspicion of a deficiency in the diet, common in those who use highly refined cereal foods. It is considered that the beneficial effects of chromium repletion are now so well established and the trivalent form is so free of toxicity that it should now be used in clinical medicine for the benefit of those with some forms of diabetes and its complications and those suffering from atherosclerosis. Of perhaps more importance is the public health aspect, since most chromium is discarded in the cereal refinement process, we now have added evidence for a return to the diets in which complex carbohydrates predominated. In those who refuse or are unable to do this, possibly the addition of chromium to their drinking water may be of value.
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PMID:Trivalent chromium, in atherosclerosis and diabetes. 180 47


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