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

Cholesterol esterase activity was estimated in homogenates of rat arterial wall using radioactive cholesteryl oleate incorporated into phospholipid vesicles as a substrate. The labeled oleic acid was separated from the ester by addition of benzene-chloroform-methanol mixture. Under these conditions, two pH optima were found at about 4.5 and 7.5. Most of the activities at pH 4.5 and 7.5 were found in the lysosomal and microsomal fraction, respectively. No enzyme activity was detected when the substrate vesicles were prepared with phosphatidylethanolamine or sphingomyelin, but the activity was higher when the substrate vesicles were prepared with phosphatidylserine and highest when they were prepared with phosphatidylcholine. The relationship between enzyme regulation and lipid deposition in the arterial wall is discussed.
Atherosclerosis 1979 Jul
PMID:Studies of cholesterol esterase in rat arterial wall. 3 82

However great the success in the therapy of hypertension, atherosclerosis and ischemic heart disease has been gained today by recent efficient drugs, the definite healing of patients is not yet attained. The late discovery of reserpine, such an efficient drug of plant origin against hypertension, convinced so far reluctant scientists to consider the chemical compounds of the plant world. With respect to this traditional medical knowledge, it seems necessary to define more accurately the specificity of these healings-sometimes recommended unspecifically for a whole branch of medicine. This experimental verification should not use inconsiderately the present-day classification of diseases; there should be an awareness that conventional experimental methods in pharmacology are often unsuitable for revealing the real biological activity of one or another medicinal plant. The interest in the millennial empirical field of health care is acknowledged by the World Health Organization which promotes research and development of traditional medicine, along with investigations into its psychosocial and ethnographic aspects. These studies cover a number of plants growing in Bulgaria that have a healing effect in hypertension, atherosclerosis and ischemic heart disease according to the data of traditional medicine. Using screening methods, extracts and chemically pure substances were investigated; extraction was done with solvents such as water, ether, chloroform, dichloretan, ethanol, methanol, and acetone. Most of the experiments were carried out on anesthetized cats, rabbits and dogs. The substances tested were applied mainly intravenously, and in some experiments orally. Chronic experiments were also carried out on wakeful dogs with induced hypertension, on animals fed on an atherogenic diet, and on animals with induced arrhythmia and coronary spasm. Data are presented of clinical examination of some plants or of active substances isolated from them. Major results of these studies are presented for the following plants: Garlic, Geranium; Hellebore; Mistletoe; Olive; Valerian; Hawthorn; Pseucedanum arenarium; Periwinkle; Fumitory. For another 50 plants growing in Bulgaria and in other countries the author presents his and other investigators' experimental and clinical data about hypotensive, antiatheromatous and coronarodilatating action.
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PMID:Plants and hypotensive, antiatheromatous and coronarodilatating action. 57 53

Using a modified liver homogenate model to assay for the inhibition of cholesterol biosynthesis, different garlic and wild garlic extracts as well as pure compounds isolated from them were investigated for their influence on cholesterol synthesis. Chloroform and acetone/chloroform extracts of garlic and wild garlic inhibited cholesterol synthesis 44-52% at a concentration of 166 micrograms/ml, while the 5 individual sulfur-containing compounds ajoene, methylajoene, allicin, 2-vinyl-4H-1,3-dithiin and diallydisulfide inhibited cholesterol synthesis by 37-72% (10(-3) M corresponding to 234, 208, 162, 144, 146 micrograms/ml, respectively). Ajoene, 2-vinyl-4H-1,3-dithiin and allicin show IC50 values of 6.4, 7.2 and 9.4 x 10(-4) M, respectively. The results demonstrate that garlic and wild garlic may reduce serum cholesterol levels primarily by inhibiting cholesterol synthesis if taken in sufficient amount and that this effect arises from a mixture of multiple compounds from the sulfur-containing class of thiosulfinates, ajoenes and dithiines. Wild garlic extracts showed nearly identical efficiency to garlic extracts.
Atherosclerosis 1992 May
PMID:Inhibition of cholesterol synthesis in vitro by extracts and isolated compounds prepared from garlic and wild garlic. 163 61

Lipid peroxidation may play a significant role in the initiation and progression of atherosclerotic plaque. Freshly harvested normal and atherosclerotic human aortic tissue, coronary arteries and explanted vein grafts were snap frozen at -70 degrees C. Folch reagent (chloroform-methanol 2:1, v/v) was used to extract lipids from the homogenates. These extracts were assayed for cholesterol, phospholipid and triglyceride content. Lipid peroxide complexes in vessels were measured fluorometrically. Atherosclerotic plaque from patients with aortic aneurysmal and occlusive disease and coronary artery disease contained significantly greater amounts of cholesterol (15.54 +/- 9.71 vs 3.39 +/- 1.14 mg/g tissue) than controls (p less than 0.01). Lipid peroxide fluorochromes were similarly elevated in all atherosclerotic tissue (4.159 +/- 1.065 vs 3.087 +/- 0.497 fluoro units/g tissue) compared to control (p less than 0.01) with significant elevations in saphenous vein grafts and occlusive aortic disease. Although lipid peroxidation and lipid accumulation occur in close association in atherosclerotic plaque, the role of lipid peroxides in the pathogenesis of atherosclerosis remains to be determined.
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PMID:Evidence for lipid peroxidation in atherosclerosis. 231 93

A technique is described which provides morphologic and quantitative data on the amount of oil red O (ORO) staining in thoracic aortas of rats fed a high cholesterol diet. Samples are stained with ORO, the dye is extracted, and the concentration of ORO in the extract is measured colorimetrically. Wistar rats fed ad libitum either standard chow (control group: n = 15) or chow supplemented with 4% cholesterol, 1% cholic acid, and 0.5% thiouracil (CCT group: n = 23) were maintained on these diets for 1, 3, 6, 9, or 12 months. Plasma cholesterol levels averaged overall 87 and 737 mg/dl for the control and CCT groups, respectively. Animals were killed under anesthesia by perfusion fixation with formalin or glutaraldehyde, and samples of thoracic aorta were stained with ORO. After microscopic study en face and measurement of surface area, the ORO was extracted in chloroform-methanol (2:1). Concentrations of ORO (microM) were determined from a standard curve and expressed as microM/mm2 of aorta. Aortas of CCT animals showed progressive diet- and time-dependent increases in the amount of ORO staining compared to controls. We conclude that this method yields reliable quantitative data applicable to studying atherosclerosis in small animals.
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PMID:Quantitation of oil red O staining of the aorta in hypercholesterolemic rats. 276 15

Calcified atherosclerotic aorta was examined for proteolipid capable of nucleating apatite, the crystal species of aortic calcification. Appropriate tissue pieces were decalcified with dilute formic acid and extracted with chloroform-methanol. Lipid fractionation yielded proteolipid which, upon incubation in metastable calcium phosphate solution, induced apatite crystallization. The proteolipid was partially characterized as a hydrophobic protein, acidic phospholipid complex. It resembles the nucleator previously demonstrated for bone matrix calcification.
Atherosclerosis 1980 Feb
PMID:Calcification by proteolipid from atherosclerotic aorta. 735 56

Cholesteryl esters are a transport and storage form of cholesterol in normal physiology but also a significant lipid in atherosclerotic plaques. To understand better the molecular properties of cholesteryl esters in tissues and plaques, we have studied the polymorphic and mesomorphic features of pure and mixed cholesteryl esters by solid state C-13 NMR with magic angle sample spinning (MASNMR). The temperature-dependent properties of two single components (cholesteryl linoleate (CL, C18:2) and cholesteryl linolenate (CLL, C18:3)), four binary systems (cholesteryl palmitate (CP, C16:0) with CL, CLL or cholesteryl oleate (CO, C18:1), and CO/CL), one ternary system (CO/CP/CL), and one quaternary system (CO/CP/CL/CLL) were studied. The mixing ratios were based on the composition of an atherosclerosis plaque dissected from a cholesterol-fed New Zealand white rabbit. C-13 MASNMR determined the phase transition temperatures, identified the phases present in all systems, and provided novel information about molecular structures. For example, solid CL exhibited a disordered structure with multiple molecular conformations, whereas pure CLL had a crystalline structure different from the three most commonly characterized forms (MLII, MLI, BL). In binary mixtures, the crystalline structure of each cholesteryl ester species was identified by its own characteristic resonances. It was found that CP always existed in its native BL form, but CL and CO were influenced by the composition of the mixture. CL was induced to form MLII crystals by the coexisting CP (55 wt%). When CO was cooled from the isotropic phase, it existed as a mixture of MLII and an amorphous form. The presence of CP significantly accelerated the conversion of the amorphous form to the MLII form. For the ternary mixture co-dried from chloroform, CL cocrystallized with CO in the MLII form and CP existed in BL form. Addition of a small amount of CLL slightly increased the heterogeneity of the solid mixture, but had little effect on the crystal structures or the phase transitions. C-13 MASNMR represents a powerful method for physical characterization of cholesteryl ester mixtures reflecting the composition of biological samples.
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PMID:Phase behavior and crystalline structures of cholesteryl ester mixtures: a C-13 MASNMR study. 764 42

Oxidatively modified LDL (oLDL) is thought to play a key role in the pathogenesis of atherosclerosis. We have studied Cu(2+)-induced peroxidation reactions of LDL and have elucidated the sequence of events which subsequently occur within LDL particles by 1H-NMR spectroscopy. Studies of chloroform/methanol extracts show that LDL arachidonate is oxidised by Cu2+ at a higher rate and to a greater extent than linoleate, giving isomeric hydroperoxides with predominantly trans,trans double-bonds, whilst only cis,trans isomers were detected as intrinsic hydroperoxides in control LDL samples. These intrinsic hydroperoxides were not degraded during peroxidation, suggesting that they are not involved in the initiation of Cu(2+)-induced peroxidation. Aldehydes arising from the decomposition of hydroperoxides were also detected, as well as saturated fatty acids which were released into the external aqueous medium. Decomposition pathways of the two major isomeric hydroperoxides are discussed. Cu(2+)-induced oxidation of LDL cholesterol appears to occur only after hydroperoxide breakdown, with esterified cholesterol being oxidised to a greater extent than free cholesterol. Phospholipid hydrolysis appeared to parallel the peroxidation of arachidonic acid, and the released lysophosphatidylcholine may become associated with apoB. These results suggest that hydroperoxide breakdown (probably in phospholipids) may be a key event in the peroxidation process, leading to the oxidation of cholesterol and propagation into the core of LDL.
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PMID:Copper-induced LDL peroxidation investigated by 1H-NMR spectroscopy. 776 90

Recent reports suggest an association between Chlamydia pneumoniae and Helicobacter pylori bacteria and atherosclerosis. We studied 51 patients (mean age, 68.3 years) who underwent abdominal aortic aneurysm surgery. For each patient we performed a microimmunofluorescence test for immunoglobulin G (IgG), IgA, and IgM antibodies to C. pneumoniae specific antigen (TW-183). Anti-H. pylori antibodies were determined by means of an EIA-G test. Each aortic aneurysm surgical specimen was sampled into multiple sections of 0.3 cm2 each and frozen at -20 degrees C. Two samples of each aneurysm were used for a nested PCR with two sets of C. pneumoniae and two sets of H. pylori specific primers. Specimens were treated with a solution containing 20 mM Tris-HCl, Tween 20-Nonidet P-40 (0.5% [vol/vol] each), and 100 micrograms of proteinase K per ml and incubated at 60 degrees C for 1 h and at 98 degrees C for 10 min. DNA was extracted twice with phenol-chloroform-isoamylic alcohol and precipitated with sodium acetate-ethanol by standard methods. Forty-one patients were seropositive for C. pneumoniae with past-infection patterns in 32 patients (16 < or = IgG < 512; 32 < or = IgA < 256) and high antibody titers in 9 patients (IgG > or = 512). In 26 of 51 patients, C. pneumoniae DNA was detected in aortic aneurysm plaque specimens. Of these patients, 23 had a serologic past-infection pattern, 2 had an acute reinfection pattern, and 1 was seronegative. Forty-seven of 51 patients were seropositive for H. pylori. In all cases PCR showed no evidence of H. pylori presence in plaque specimens. This study provides data on a possible C. pneumoniae involvement in the pathogenesis of aortic aneurysm and additional evidence for an association between this agent and atherosclerosis. Conversely, notwithstanding a high H. pylori seroprevalence observed, our results tend to rule out the possibility of a direct involvement of H. pylori in atherosclerosis.
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PMID:Detection of Chlamydia pneumoniae but not Helicobacter pylori in atherosclerotic plaques of aortic aneurysms. 889 80

We have investigated the effects of oxidized low density lipoproteins (oxidized LDL) on the expression of TM by THP-1 monocytic cells. TM antigen levels and its cofactor activity for thrombin-dependent protein C activation were increased by oxidized LDL and accompanied by an increase in TM mRNA levels. Incubation of THP-1 cells with 300 microg/ml oxidized LDL for 24 h resulted in an 80% increase of cellular TM antigen levels. Native LDL and acetylated LDL did not affect the TM expression by these cells. The resultant aqueous phase after extraction of oxidized LDL by chloroform/methanol increased the TM antigen levels as well as oxidized LDL. Phorbol 12-myristate 13-acetate (PMA) also increased the TM antigen level 2.1 times the control and was accompanied by the adhesion of cells to plastic dishes and increasing macrophage cell surface antigen CD14 levels. In contrast, oxidized LDL did not induce differentiation to the macrophage. The present results indicate that oxidized LDL increases cellular TM antigen without cellular differentiation and that up-regulation of TM by oxidized LDL in monocytes may have some implication in atherosclerosis.
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PMID:Effect of oxidized low density lipoprotein on thrombomodulin expression by THP-1 cells. 936 89


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