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

Elastin from bovine ligamentum nuchae is exposed to aqueous solutions of different alkyl sulfates and carboxylates (fatty acids). The substrates of alkyl chain lengths varying between C8 and C17 bind to the elastin, the more so the longer the alkyl chain. However, the presence of two (or more) double bonds in the chain obstructs the penetration into the elastin network. As a result of absorption the elastin swells. The rate of binding is determined from the swelling of an elastin strip, that is monitored using a cathetometer. The diffusion of the substrate in the elastin is slower the longer the alkyl chain. The binding is reversible so that the Gibbs energy involved can be derived from the absorption isotherm. The values for the Gibbs energy of binding may amount to some tens of kJ per mol of substrate, with an increment of -4 kJ mol-1 per CH2 group. From the influence of temperature it is concluded that the binding is entropically driven. This, as well as the observation that the glass transition temperature of elastin is not affected by the presence of the alkyl derivatives, suggests that the substrates are bound to the amino acid residues of the elastin, rather than to the polypeptide backbone. Stress-strain experiments reveal that the elasticity decreases markedly on swelling of the sample, irrespective of the type of substrate that is absorbed. The phenomena described in this paper may be similar to those that occur between fatty acids in blood and arterial elastin, which could be at the origin of the development of atherosclerosis.
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PMID:The interaction between alkyl derivatives and elastin. 397 15

A unifying concept that excessive proliferation of cells and turnover of cellular matrix contribute significantly to the pathogenesis of several diseases, including cancer, atherosclerosis, rheumatoid arthritis, psoriasis, idiopathic pulmonary fibrosis, scleroderma and cirrhosis of the liver, is presented. As corollaries to this concept, the following topics are considered: (1) the role of polypeptide hormones and hormone-like mediators in the initiation, promotion and maintenance of proliferative responses; (2) alterations in collagen metabolism and collagenase activity; (3) the role of proteinases; (4) the potential use of inhibitors of proteinases for prevention of disease; and (5) the potential use of inhibitors of proliferative polypeptide hormones for prevention of disease. As specific proteolytic and proliferative biochemical mechanisms which contribute to the pathogenesis of disease become identified, there is a unique opportunity to develop new pharmacologic methods of prevention.
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PMID:Proliferative diseases. 626 92

Epidemiological studies have identified elevated low density lipoprotein (LDL) and diminished high density lipoprotein (HDL) cholesterol levels as risk factors for coronary artery disease. The major protein component of HDL is apoprotein A-I (apo A-I), a polypeptide of 243 amino acids of known primary amino acid sequence. This apoprotein serves as a cofactor for the plasma lecithin-cholesterol acyltransferase (LCAT) enzyme responsible for the formation of most cholesteryl esters in plasma, and also promotes cholesterol efflux from cells. The primary translation product of apo A-I contains both a pre and a pro segment, and post-translational processing of apo A-I may be involved in the formation of the functional plasma apo A-I isoproteins. Defective apo A-I processing may be the underlying problem in Tangier disease, in which patients have low plasma HDL and apo A-I levels despite normal apo A-I synthesis. Patients have been reported with conditions distinct from Tangier disease in whom severe deficiency or absence of apo A-I has been associated with very low HDL levels and severe coronary artery disease. We have now examined the apo A-I gene in two such patients and their first degree relatives. These patients have been reported to have skin and tendon xanthomas, corneal clouding and severe premature coronary atherosclerosis associated with very low HDL levels and deficiencies of two apoproteins, apo A-I and apo C-III. We show that both probands are homozygous for a defect in the apo A-I gene locus.
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PMID:An inherited polymorphism in the human apolipoprotein A-I gene locus related to the development of atherosclerosis. 640 11

In the past years, the structure and function of the plasma lipoproteins and apolipoproteins have been elucidated. The biochemical defect of several genetic lipoprotein disorders and their role in the development of atherosclerosis are now well understood. Electrophoretic separation of lipoproteins in polyacrylamide gradient gel gives an acurate characterization of the different lipoproteins and allows the phenotyping of hyperlipoproteinemia. Abnormal concentrations of plasma lipoproteins have been known for many years to be a major risk factor in the development of premature ischemic heart disease. Although large-scale epidemiological studies have focused attention on the association between above-normal concentrations of plasma lipids and coronary atherosclerosis, recent findings have shown that quantitative lipoprotein and apoprotein determination may be a more nearly accurate predictor in the recognition of atherosclerosis. The risk for vascular disease seems to be particularly associated with an increase in the concentrations of apolipoprotein B (apo B), the major protein moiety of low density lipoproteins and a decrease in apolipoprotein Al, the major polypeptide of high-density lipoproteins.
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PMID:[Methods of biochemical analysis in hyperliproproteinemias]. 640 90

Plasma lipids (cholesterol, triglycerides) which are essentially hydrophobic components circulate as lipid-protein complexes. Lipoproteins are defined by their protein moiety (apoprotein) whose composition corresponds to their density class. Low density lipoproteins are characterized by apoprotein B; in contrast, apoproteins A are found in high density lipoproteins. Apoproteins, consisting of a single or several polypeptide chains, play an essential role not only as structural entities but also as functional units in relation to the enzymes of lipoprotein metabolism. It is therefore possible that apoproteins may occupy a major place in the physiopathology of dyslipoproteinemias. To date, their roles have been established in atherosclerosis and some hyperlipoproteinemias with hypertriglyceridemia. Future studies of apoproteins may give a better understanding of certain other poorly defined metabolic disorders. At present, some of the hyperlipoproteinemias have been characterized by variations of one or several apoprotein levels. Nevertheless, the interpretation of this data must be cautious in view of a number of unknown factors.
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PMID:[Apoproteins in dyslipoproteinemia (author's transl)]. 678 29

Humoral regulation of somatic and hematopoietic cell growth has been intensely investigated during the past decade. Growth hormone is unique because it regulates the size of the person within the constraints of the genetic program. The somatomedins and insulin growth factors are low molecular weight polypeptides believed to mediate some functions of growth hormone. Epithelial growth factor and nerve growth factor are well-characterized polypeptides that influence the growth and differentiation of epithelial and neural tissues and interact with specific cell surface receptors. The hematopoietins are a family of polypeptide hormones that specifically regulate the proliferation and differentiation of stem cells giving rise to erythrocytes, granulocytes, monocytes, megakaryocytes, and B and T lymphocytes. Platelet-derived growth factor modulates the proliferation of fibroblasts in vitro and may have a role in the development of atherosclerosis and myelofibrosis. New knowledge on the biochemistry and physiology of growth factors will probably have a substantial impact on our understanding of human diseases involving abnormal cell growth.
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PMID:Growth factors. 699 74

The polypeptide composition of a variant lipoprotein (d less than 1.006) carrying a relative excess of apolipoprotein C-II has been characterised by polyacrylamide gel electrophoresis and isoelectric focussing. The apo-C peptides of the variant lipoprotein contained 45.2 +/- 1.3 (n = 9) % of apo C-II compared with 21.5 +/- 5.4 (n = 30) % for hypertriglyceridaemic controls. The variant lipoprotein activated purified bovine milk lipoprotein lipase normally, but was an inefficient substrate for this enzyme as assessed by direct release of fatty acids from the lipoprotein or by a substrate competition assay. Electron microscopy revealed the variant lipoprotein as non-spherical flattened particles compared with the more spherical appearance of control triglyceride-rich lipoproteins. We suggest that the relative proportion of apo C peptides associated with the lipoprotein particle may be critical for optimal enzyme-substrate interaction.
Atherosclerosis
PMID:An abnormal triglyceride-rich lipoprotein carrying excess apolipoprotein C-II. 747 Jan 92

Review article informs about the physiological and pathophysiological effects of the most potent vasoconstrictor agent endothelin (ET). This vasoactive polypeptide (21-aminoacid) has three izoforms (ET-1, ET-2, ET-3) and participates on regulation of the vascular tone and on remodelling of the vascular and myocardial wall. Article is focused on the effects of endothelins on the cardiovascular system, kidney and the central nervous system with respect to their expected role in the initiation and sustaining of disorders and diseases accompanied by the local and general vasconstriction. Findings concerning the role of endothelins in the pathogenesis of arterial hypertension, myocardial infarction, congestive heart failure, atherosclerosis, shock conditions, renal failure, and vasospasm following the subarachnoidhem orrage are discussed.
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PMID:[Endothelin--a cardiovascular regulatory peptide. II. Outline of its pathophysiologic activity]. 758 20

The dipolar-decoupled, natural abundance Fourier transform and cross polarization [13C] NMR spectra of human elastin isolated from atherosclerotic aorta and aortas free of atherosclerotic lesions, bovine insoluble elastin and bovine kappa-elastin were obtained at 75 MHz, with 5-7 kHz magic angle sample spinning. Spin-lattice rotating frame relaxation parameters were measured for protons (T1pH) and for carbons (T1pC) at room temperature. Proton relaxation times were shorter for bovine kappa-elastin (T1pH = 1.7 ms) than for bovine elastin (T1pH) = 3.5 ms). Calculation of T1pH showed no differences between human normal and atherosclerotic elastins. T1pC were shorter for bovine kappa-elastin than for bovine elastin. While alpha-carbons of human atherosclerotic elastin had shorter T1pC than normal elastin alpha carbons, carbons from hydrophobic amino acid side chains had longer T1pC for atherosclerotic then for normal elastin. Biochemical studies of aortic wall and purified elastin showed significantly increased content of lipids (atherosclerotic 67.7 mmol/g elastin, control 54.7 mmol/g elastin) and calcium (atherosclerotic 38.3 mmol/g elastin, control 19.6 mmol/g elastin). Changes in relaxation parameter values may be caused by the structural and biochemical changes in human elastin. Increased mobility of polypeptide chains as based on the model kappa-elastin studies is caused by the action of elastase. Restriction of mobility is expected to be caused by the accumulation of lipids and calcium.
Atherosclerosis 1995 May
PMID:Changes in elastin in human atherosclerotic aorta: carbon-13 magic angle sample-spinning NMR studies. 766 85

The aim of this review is to summarize the current concepts concerning the active role of the endothelium in the pathogenesis of atherosclerosis. Activated endothelium may promote the adhesion of monocytes and their transmigration into the intima. The coordinated expression of adhesion molecules of the selectin, integrin or immunoglobulin superfamily on the surface of endothelial cells and of monocytes modulates these events. The role of lipoproteins and their oxidative derivatives as well as that of selected cytokines and platelet activated factor in initiating changes on the endothelial cell surface has been investigated: these events are associated with an increased endothelial permeability to lipids and lipoproteins with their accumulation in the subendothelium. Once migrated into the intima, monocytes undergo morphological and functional modifications leading to the generation of a polypeptide mediator network which is instrumental in the migration, differentiation and proliferation of smooth muscle cells. Mediators produced by macrophages infiltrating the atherosclerotic plaque and by the endothelium may render the surface of the endothelial cells thrombogenic thus favoring thrombotic occlusion. In conclusion, the most recent studies suggest that the endothelium plays an active role in the pathogenesis of atherosclerosis.
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PMID:[Functional changes of the endothelium and atherosclerotic process]. 772 4


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