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

It has been shown that monocytes are present in early atherosclerotic lesions and in mechanically-injured arterial intima, but direct morphological tracing of specific leukocyte populations into such areas has been lacking. A method for FITC-labelling of leukocytes was therefore evaluated for monocyte studies. Monocyte (95% pure) populations were isolated from blood by counterflow centrifugation and labelled by incubation with free fluorescein isothiocyanate 1-hydrochloride (FITC) in Hank's balanced salt solution. FITC-labelled monocytes showed glass adherence, spreading and migration, as well as acid phosphatase positivity and phagocytosis for up to 20 days in tissue culture. For in vivo experiments, hypercholesterolemic (H) and normal (N) swine were bled repeatedly, and monocyte populations were isolated, labelled and reinjected. Labelled cells were found in blood samples. Animals were killed after 9 days, and formaldehyde-fixed and frozen samples of aortae were studied en face and/or sectioned and examined microscopically under fluorescence. FITC-labelled leukocytes could be found adherent to sites of thickened intima but not to normal areas. Labelled cells were also detected within atherosclerotic lesions. These results show the feasibility of the labelling technique and provide direct visualization of monocyte recruitment from the blood into atherosclerotic and lesion-prone areas.
Atherosclerosis 1988 May
PMID:Visualization of monocyte recruitment into atherosclerotic arteries using fluorescent labelling. 313 79

The oxidation of low-density lipoprotein (LDL) may be important in the pathogenesis of atherosclerosis. However, the interactions between cells and metals in promoting LDL oxidation are inadequately understood. A sensitive high-performance liquid chromatography analysis of cholesterol, cholesteryl esters, and their oxidation products was used to identify and accurately measure LDL oxidation achieved in thiol-free Hanks' balanced salt solution (HBSS) at pH 7.4. Mouse peritoneal macrophages inhibited LDL oxidation when incubated in HBSS containing either 10 microM iron or 1 microM copper, but were markedly prooxidant in the presence of both metals. The prooxidant effect of macrophages in the presence of both iron and copper did not require the provision of added disulfides or thiols. Both Fe2+ and macrophages were demonstrated to independently reduce Cu2+ to Cu1+ in HBSS, indicating that the direct reduction of copper by cells or iron may underlie the observed promotion of LDL oxidation by macrophages in this system. We conclude that macrophages can either promote or inhibit metal-mediated LDL oxidation and that externally supplied thiols are not essential to the promotion of LDL oxidation by cells. The presence of both iron and copper may be particularly important for macrophages to promote LDL oxidation in vivo.
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PMID:Macrophages require both iron and copper to oxidize low-density lipoprotein in Hanks' balanced salt solution. 748 58

Oxidized low density lipoprotein (LDL) may play a significant role in atherosclerosis. We have investigated the effect of pH on the oxidation of LDL by iron or copper. When LDL was oxidized by iron in the presence of cysteine in either Hanks' balanced salt solution (HBSS) or Ham's F-10 medium, an acidic pH greatly decreased the lag period and increased the rate of formation of hydroperoxides and thiobarbituric acid-reactive substances (TBARS), and increased its uptake by macrophages. There was a dose-dependent increase of LDL oxidation at acidic pH in the presence of increasing concentrations of cysteine. When LDL was oxidized by copper in HBSS, an acidic pH increased the lag phase before the rapid formation of conjugated dienes, hydroperoxides, and TBARS, but increased its uptake by macrophages. Similar results were obtained using Ham's F-10 medium. Cysteine (100 microM) inhibited the modification of LDL by copper in HBSS at both pH 7.4 and 5.5 As atherosclerotic lesions may be acidic, these observations may help to explain why LDL oxidation occurs locally at these sites.
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PMID:Oxidation of low density lipoprotein by iron or copper at acidic pH. 884 77