Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0004153 (atherosclerosis)
 77,401 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Cholesteryl esters have been incorporated into phospholipid vesicles up to 5 mole percent. Excess ester separates out into a separate phase which resembles the mesomorphic droplets of atherosclerosis. The incorporation of 5 mole percent cholesteryl palmitate is shown by 31P NMR studies to increase the permeability of the model membranes to ions 10-fold. The same incorporation of cholesteryl linoleate does not affect the membrane permeability. Implications of these findings, and the significance of the cholesteryl ester/free cholesterol ratio upon atherosclerosis is discussed.
Atherosclerosis 1977 Nov
PMID:Cholesterol esters and membrane permeability. A nuclear magnetic resonance (MNR) study. 41 55

Magnetic resonance imaging (MRI) has been proposed as a potential tool in the evaluation of atherosclerotic lesions. However, two basic difficulties have to date prevented the full exploitation of the potentials of this technique: the poor spatial resolution of the conventional tomographs and the wide variety of the lesions as well as their intrinsic dishomogeneity. In this study the in vitro morphology of normal and atherosclerotic vascular tissue specimens has been evaluated using a high resolution spectometer equipped with a microimaging device. Morphological features of the vessel walls as small as 10(-1) mm have been detected and the distribution of lipids and of calcified or necrotic regions has been evidenced in atherosclerotic plaques. Different techniques, such as local spectroscopy performed on volumes of 1 mm3 and localized magnetization recovery measurements, have been employed to characterize specific regions of the vessel walls from the chemical and the physical point of view. The good agreement of NMR findings with histological data allows us to conclude that NMR microimaging represents a suitable technique for the in vitro detection and characterization of atheromatous lesions.
Atherosclerosis 1990 Jan
PMID:Evaluation of atherosclerotic lesions using NMR microimaging. 231 Apr 30

Follow-up of bypass patients in the early postoperative phase involves the management of complications such as perioperative myocardial infarction, postoperative arrhythmias, pericarditis, postcardiotomy-syndrome, fever, infection and chest pain. The longterm management has to focus on changes in lifestyle with particular regard to risk factors for coronary atherosclerosis. Diagnostic tools for work-up of postoperative chest pain include stress testing and radionuclide techniques; ultrafast computerized tomography is superior in the evaluation of bypass function to cine-NMR. Conventional angiography is still the only method to reliably visualize graft patency and anastomotic sites. Indications for reoperations can be well defined.
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PMID:[Care of patients following coronary bypass surgery from the internist's viewpoint]. 236 17

High resolution 1H and 13C NMR spectroscopic measurements including 1H/13C 2D correlation and magnetic resonance imaging (MRI) studies, have been carried out on intact rabbit aortic tissues ex vivo using animals fed both normal and high cholesterol diets. The results show that 1H and 13C NMR spectroscopy can distinguish mobile lipids and can differentiate between normal triglyceride content and cholesterol-enriched lipids, in intact tissue, There were considerable differences in the level of deposition of cholesteryl esters in animals all fed on the same diet. Confirmation is presented of temperature-dependent differences in mobility and organization between the triglycerides found in control tissue and the cholesteryl esters found in aortas from high lipid diet animals. Water-suppressed MRI showed evidence of lipid accumulation in the aortas of high cholesterol diet rabbits. It is concluded that the hypercholesterolaemic rabbit model of atherosclerosis, coupled with such NMR methods, may offer a noninvasive method of monitoring disease development, allowing the evaluation of the effect of therapeutic agents on the progress of atherosclerosis.
NMR Biomed 1990 Apr
PMID:Lipid characterization in an animal model of atherosclerosis using NMR spectroscopy and imaging. 239 Apr 59

The non-invasive measurement of vascular dynamics and elasticity is critical in understanding haemodynamic conditions of cardiovascular diseases such as hypertension and atherosclerosis. Although there are numerous invasive and in vitro techniques for such measurements, until now non-invasive methods have been limited. We have now obtained stroboscopic NMR images of the carotid arteries of 80-g rats. The change in the cross-sectional area of arteries of diameter approximately 600-800 microns was correlated with the change in absolute blood pressure. These are the first microimages of a dynamic system and enable the direct visualization of compliance, the non-invasive measurement of Young's modulus, the direct determination of the local effects of vasoconstrictors and vasodilators and the mapping of the entire cardiac cycle.
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PMID:Stroboscopic NMR microscopy of the carotid artery. 279 48

Coronary artery disease due to atherosclerosis takes the lives of approximately 550,000 Americans each year--an enormous toll. Put in economic terms, the cost to the United States alone has been estimated to exceed 60 billion dollars annually. We have found that well-resolved proton (1H) NMR spectra can be obtained from human atheroma (fatty plaque), despite its macroscopic solid appearance. The fraction of the total spectral intensity corresponding to the sharp 1H NMR signals is temperature dependent and approaches unity at body temperature (37 degrees C). Studies of the total lipids extracted from atheroma and cholesteryl esters were conducted to identify the chemical and physical origin of the spectral signature. The samples were characterized through assignment of their chemical shifts and by measurement of their T1 and T2 relaxation times as a function of magnetic field strength. The results suggest that the relatively sharp 1H NMR signals from human atheroma (excluding water) are due to a mixture of cholesteryl esters, whose liquid-crystalline to isotropic fluid phase transition is near body temperature. Preliminary applications to NMR imaging of human atheroma are reported, which demonstrate early fatty plaque formation within the wall of the aorta. These findings offer a basis for noninvasive imaging by NMR to monitor early and potentially reversible stages of human atherogenesis.
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PMID:High-resolution 1H NMR spectral signature from human atheroma. 320 43

The effect of Anna Pavala Sindhooram (APS), an indigenous drug showing lipid lowering action was tested in experimental rat atherosclerosis induced by feeding an atherogenic diet. APS was found to decrease the levels of serum cholesterol and phospholipids while triglycerides remained unaffected in atherogenic diet fed rats. Lipid levels in the aorta, liver and intestine were also increased by atherogenic diet feeding, and APS administration with diet restriction reversed this trend. Cholesterol ester was lowered. Both cholesteryl ester hydrolase (CEH) and synthetase (CES) activities in the tissues were elevated while the CEH/CES ratio was lowered in atherosclerosis. APS administration led to a decrease in enzyme activities and an increase in the CEH/CES ratio. APS in vitro inhibited both enzyme activities. NMR spectroscopic studies showed that the soluble components of APS bind or modify cholesterol. Iron, copper, magnesium and calcium present in APS may play a role in the removal of cholesterol ester from the aorta and its disposal.
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PMID:Lipids and cholesterol esterifying enzyme changes by Anna Pavala Sindhooram therapy in experimental rat hyperlipaemia. 663 36

We sought to determine whether 1H NMR images without chemical-shift selection can adequately characterize the components of human atheromatous arteries. NMR, as a nondestructive, biochemical imaging tool, has the potential to identify lipids in atherosclerotic plaques but has not yet produced detailed images of atheroma components. Using 1H NMR spectroscopy at 9.4 T, we examined microdissected components of diseased and normal arteries to determine water relaxation constants (T1 and T2) as well as the relative content of mobile lipid. Relaxation times were also measured at 1.5 and 4.7 T. Sections of arteries with atherosclerotic lesions of graded severity were imaged at 1.5 and 9.4 T. The contrast-to-noise ratio (CNR) was used to assess lesion conspicuity. In the atheromatous core, the water NMR signal predominates over that of lipid (lipid-to-water ratio, 0.11). At 9.4 T, T2 is 20.2 ms for the atheromatous core, 30.1 ms for the collagenous cap, and 29.5 ms for normal media. This results in a high CNR on T2-weighted (T2w) images for atheromatous core compared with the collagenous cap and normal media. A similar contrast was measured at lower field strength. Calcifications do not generate appreciable signal due to their low water content but can be detected on T1-weighted (T1w) images. The water T2 contrast allows discrimination of the atheromatous lipid core from collagenous regions. The combination of T1w and T2w sequences permits in vitro identification of the atheromatous core, collagenous cap, calcifications, media, adventitia, and perivascular fat. The discrimination of collagen fibers that overlie lipid deposits permits study of plaque protection and stability at all field strengths and may provide the basis for in vivo microscopy of human atherosclerosis.
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PMID:T2-weighted contrast for NMR characterization of human atherosclerosis. 758 24

The low-density lipoprotein (LDL) receptor plays a central role in mammalian cholesterol metabolism, clearing lipoproteins which bear apolipoproteins E and B-100 from plasma. Mutations in this molecule are associated with familial hypercholesterolemia, a condition which leads to an elevated plasma cholesterol concentration and accelerated atherosclerosis. The N-terminal segment of the LDL receptor contains a heptad of cysteine-rich repeats that bind the lipoproteins. Similar repeats are present in related receptors, including the very low-density lipoprotein receptor and the LDL receptor-related protein/alpha 2-macroglobulin receptor, and in proteins which are functionally unrelated, such as the C9 component of complement. The first repeat of the human LDL receptor has been expressed in Escherichia coli as a glutathione S-transferase fusion protein, and the cleaved and purified receptor module has been shown to fold to a single, fully oxidized form that is recognized by the monoclonal antibody IgG-C7 in the presence of calcium ions. The three-dimensional structure of this module has been determined by two-dimensional NMR spectroscopy and shown to consist of a beta-hairpin structure, followed by a series of beta turns. Many of the side chains of the acidic residues, including the highly conserved Ser-Asp-Glu triad, are clustered on one face of the module. To our knowledge, this structure has not previously been described in any other protein and may represent a structural paradigm both for the other modules in the LDL receptor and for the homologous domains of several other proteins. Calcium ions had only minor effects on the CD spectrum and no effect on the 1H NMR spectrum of the repeat, suggesting that they induce no significant conformational change.
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PMID:Three-dimensional structure of a cysteine-rich repeat from the low-density lipoprotein receptor. 760 91

Diagnosis and prognosis of atherosclerosis can no longer be evaluated with morphological parameters only. A description of atherosclerotic plaque composition is necessary to study the mechanisms of plaque rupture, which depends on collagenous cap and lipid core thicknesses. NMR, as a biochemical imaging technique, allows visualization of these components using T1 contrast (mobile lipids), T2 contrast (cap vs. core), spin density (calcifications), diffusion imaging, 1H and 13C spectroscopy. Today, these imaging sequences allow to study in vitro the effects of interventional techniques such as angioplasty or atherectomy. Clinical investigations begin, which will attempt to develop in vivo microscopy and test the ability of NMR to predict plaque rupture.
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PMID:[Role of NMR in the diagnosis of atherosclerosis]. 763 20


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