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Results 601 - 650 of 740
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Aviram M - - 1994
Macrophage degradation of low density lipoprotein (LDL) was shown to be increased in lipopolysaccharide (LPS)-stimulated cells. The involvement of second messengers in this phenomenon was studied. Preincubation of J-774A.1 macrophages with the protein kinase C (PKC) inhibitors D-sphingosine or staurosporine did not significantly affect the stimulatory action of LPS. Similarly, ...
Bernhagen J - - 1994
The cytokine macrophage migration inhibitory factor (MIF) is a major protein constituent of the anterior pituitary gland released into the bloodstream during endotoxaemia. For many years, MIF had been thought to be a T cell product associated with delayed-type hypersensitivity reactions. The identification of MIF as a pituitary 'stress' hormone ...
Fong L G - - 1994
The regulation of the macrophage-induced oxidation of low density lipoprotein (LDL) by cytokines was investigated. As an initial source of cytokines, medium from an activated type 2 helper T-cell clone was tested. This cell-free supernatant inhibited the subsequent oxidation of LDL by mouse peritoneal macrophages. The inhibition was concentration- and ...
Sporeno E - - 1994
Oncostatin M is a cytokine that acts as a growth regulator on a wide variety of cells and has diverse biological activities including acute phase protein induction, LDL receptor up-regulation and cell-specific gene expression. In order to gather information about the Onc M structure, we established a protocol for large ...
Shiratori Y - - 1994
Atheroma macrophages accumulate large amounts of free cholesterol (FC) as well as cholesteryl ester (CE). An important adaptive response to FC loading might be increased cellular phospholipid to accommodate the excess FC. To explore this idea, J774 macrophages were incubated for 48 h without lipid, with acetyl-low density lipoprotein to ...
Contreras J A - - 1994
Cholesteryl ester-laden macrophages are the hallmark of the fatty streaks that precede arteriosclerotic plaques in humans and experimental animals. This article studies several aspects of cytoplasmic cholesteryl ester metabolism in cultured human monocyte-derived macrophages. Adenosine 3',5'-cyclic monophosphate (cAMP) consistently inhibited cholesteryl ester mobilization from cells that had been loaded with ...
Maziere C - - 1994
The effect of tumor necrosis factor on the oxidative modification of LDL by U937 human monocytes or murine endothelial cells was studied by determination of the lipid peroxidation product content and the electrophoretic mobility of the particle. In the range of concentrations from 2.5 to 10 ng/ml, the cytokine induced ...
Matthys K E - - 1994
Activated cholesterol-laden macrophages in atherosclerotic lesions are believed to influence the progression of this disease. The induction of nitric oxide synthase (iNOS) activity was investigated in control and cholesterol-laden J774 macrophages, obtained by pre-incubation with oxidized or acetylated low density lipoproteins (oxLDL, acLDL). Loading with oxLDL caused a small induction ...
Ettinger W H - - 1994
Cytokines, important biochemical mediators of inflammation, cause a rapid fall in the plasma concentration of cholesterol in vivo. One mechanism by which cytokines may cause acquired hypocholesterolemia is by decreasing the hepatic synthesis and secretion of apolipoproteins. To test this hypothesis, we incubated Hep G2 cells with human recombinant tumor ...
Lopes-Virella M F - - 1993
It has been proposed for several decades that infections may be responsible for the accelerated development of atherosclerosis. Numerous studies have shown an association between atherosclerosis and both viral and bacterial infections. In this review, we summarize the evidence linking infections with abnormalities in lipid and lipoprotein levels and the ...
Bernhagen J - - 1993
Cytokines are critical in the often fatal cascade of events that cause septic shock. One regulatory system that is likely to be important in controlling inflammatory responses is the neuroendocrine axis. The pituitary, for example, is ideally situated to integrate central and peripheral stimuli, and initiates the increase in systemic ...
Wu J - - 1993
IL-10, in addition to being a cytokine synthesis-inhibitory factor, is a cytokine that exerts multiple effects on various cell types. Recombinant human migration inhibitory factor (MIF) inhibits the migration of human monocytes as well as that of guinea pig and murine macrophages. In addition, it has recently been shown to ...
Zuckerman S H - - 1993
Macrophage apo E synthesis and secretion has been previously demonstrated to be regulated by intracellular free cholesterol levels and is decreased by cytokines and other inflammatory stimuli associated with macrophage activation. In a recent study, the opposing effects of TGF beta and GM-CSF were reported with the former increasing and ...
Evans A J - - 1993
The present investigations have examined the mechanism(s) whereby Sf 60-400 very low density lipoproteins (VLDL) from Type IV hypertriglyceridemic subjects cause cholesteryl ester and triglyceride accumulation in J774 macrophages. Both apolipoprotein (apo) E-poor and apoE-rich Type IV VLDL subfractions, isolated by heparin-Sepharose chromatography, were capable of enhancing cellular cholesterol and ...
Bottalico L A - - 1993
Lipoprotein(a) levels in the plasma are strongly correlated with atherosclerotic coronary artery disease. Although the mechanism of this effect is not known, the interaction of lipoprotein(a) with macrophages may be important. Previous work has shown that macrophages in culture internalize and degrade native lipoprotein(a) poorly. In the present study, the ...
de Ricqlès D - - 1993
We have previously reported that breast cancer patients and some healthy subjects show positive T-cell-mediated immune responses to a semi-purified mouse mammary tumour viral pool (MMTV). We have now used Western blotting to analyse the specificity of the response and to determine the target polypeptides. Two types of T-cell response ...
Skarlatos S I - - 1993
Lipoprotein lipase, a lipolytic enzyme essential for normal hydrolysis of triglycerides in very low density lipoprotein (VLDL) and chylomicrons, is found in several cell types, including macrophages. The role of lipoprotein lipase in mediating the uptake of normal VLDL triglycerides into human cultured monocyte-derived macrophages was studied using macrophage cells ...
Yui S - - 1993
We previously reported that cell membrane components and lipoproteins were able to induce the growth of murine peritoneal macrophages. The aim of the present study was to examine whether macrophage growth could also be induced by chemically modified lipoproteins, such as acetylated low density lipoprotein (acetyl-LDL) or oxidized LDL, ligands ...
Schwartz C J - - 1993
Two key events in the atherogenic cascade are the focal influx and accumulation of low-density lipoprotein (LDL) cholesterol at arterial sites having a predilection for atherosclerotic lesion development and the recruitment of blood monocytes to these lesion-prone sites. Both processes are enhanced in the setting of hyperlipidemia and dyslipoproteinemia. The ...
Aviram M - - 1993
Modified forms of low density lipoprotein (LDL) are associated with increased atherogenicity. Modified LDL, in comparison with native LDL, demonstrates enhanced cellular uptake by macrophages, foam cell formation and also causes the secretion of cytokines and growth factors from arterial wall cells. Non-enzymatic modifications of LDL (proteoglycans, glycosylation, immune complexes) ...
Blocki F A - - 1992
Mammals have separate enzymatic and cellularly mediated detoxification systems. Glutathione S-transferases (GSTs) protect against xenobiotic chemicals which continuously enter the body, largely through mucous membranes. These enzymes catalyse the conjugation of glutathione with a wide variety of electrophilic compounds rendering them non-toxic. Mammals also mount a cellular immunological response on ...
Lopes-Virella M F - - 1992
It was recently proposed that the increased levels of modified lipoproteins in diabetic patients may be responsible for the accelerated development of macrovascular complications associated with the disease. Modified lipoproteins are believed to induce the transformation of macrophages into foam cells and, in some cases, to induce endothelial cell damage. ...
Yates M T - - 1992
Low density lipoproteins (LDL) oxidatively modified by macrophages have been shown to be atherogenic in ex vivo studies. We studied the potential role of nitric oxide (NO), a free radical produced by macrophages, in LDL modification. Human LDL (1 mg/ml) were incubated with mouse peritoneal macrophages in Ham's F-10 medium. ...
Roma P - - 1992
In J774 murine macrophages, chemically oxidized LDL (OxLDL) and biologically oxidized LDL (BioOxLDL) have similar metabolic fates, characterized by a relatively poor degradation when compared with acetylated LDL (AcLDL), and a modest ability to activate acyl-CoA:cholesterol acyltransferase (ACAT) (850 and 754 pmol [14C]oleate/mg cell protein in OxLDL- and BioOxLDL-incubated cells, ...
Oiknine J - - 1992
Inflammation is associated with macrophage activation, and this process has been shown to occur during atherogenesis. Macrophages (J774A.1) that were activated with either lipopolysaccharide (LPS), zymosan, or phorbol ester demonstrated a 30-35% increased uptake and degradation of low density lipoprotein (LDL) in comparison with nonactivated cells. This phenomenon was also ...
Grove R I - - 1991
Recent evidence suggests the possibility that macrophages can influence lipoprotein metabolism. Therefore we investigated the ability of cultured macrophages to alter low density lipoprotein (LDL) uptake in a human liver cell line (HepG2). Conditioned media from phlogogenic-induced mouse peritoneal macrophages or from a human macrophage cell line stimulated with endotoxin ...
Horváth M - - 1991
The immunomodulatory effect of the lipid-reducing etofibrate, the calcium antagonist nifedipine and the immunosuppressive cyclosporine A was studied on in vitro cellular immune response in the presence of human aortic extract and of human LDL in 56 patients with acute myocardial infarction. 50 sex- and age-matched healthy persons were used ...
Grunfeld C - - 1991
The hypertriglyceridemia of infection is produced by many of the cytokines that regulate the immune response, including the tumor necrosis factors, interleukin-1, interleukin-6, and the interferons. In rodents, this hypertriglyceridemia is primarily due to the ability of these cytokines to stimulate hepatic lipogenesis and very low density lipoprotein production without ...
Griffin H - - 1991
The results of the present study strongly suggest that the hypertriglyceridaemia in chicks treated with Aroclor 1254 is a result of reduction in VLDL clearance rather than an increase in rate of VLDL secretion. The decrease in post-heparin LPL activity responsible for reduced VLDL clearance may be mediated by cytokines ...
Mehta U - - 1991
The present study was addressed to understand two specific issues: (a) whether atherogenic activity of smooth muscle cells could be initiated by incorporating cholesterol within their membranes through a LDL-receptor-independent pathway; and (b) whether trifluoperazine, which we had recently shown to prevent the cholesterol-induced atherogenesis in an experimental animal model ...
Devi R S - - 1991
Rats with bilateral electrolytic ventral hippocampal formation (VHF) lesion show a significantly (p less than 0.001) enhanced migration of leucocytes in the presence of antigen. Immunization in these animals enhances (p less than 0.001) the leucocyte migration and presents a significant decrease in footpad thickness. Antibody titre (p less than ...
Nigon F - - 1991
We have evaluated the effect of native low-density lipoproteins (LDL) on the production of leukotriene B4 (LTB4), a potent inflammatory and chemotactic factor, by human monocyte-derived macrophages. The capacity of LDL (d, 1.024-1.050 g/ml) to increase LTB4 secretion was dose-dependent with an optimal response at 100 micrograms LDL protein/ml, representing ...
Gisinger C - - 1991
We have recently shown that incubation of macrophages with insoluble immune complexes (IC) containing low-density lipoproteins (LDL) leads to intracellular accumulation of esterified cholesterol (CE). This accumulation is associated with morphological transformation of the macrophages into "foam cells." In order to better characterize the conditions that lead to the uptake ...
Rankin S M - - 1991
It has been suggested that the oxidative modification of low density lipoprotein (LDL) is a key event in atherogenesis. Several mechanisms have been proposed to explain how different types of cells modify LDL. In this study we examine the relative contributions of superoxide anions and cellular lipoxygenase (LO) in the ...
Srinivasan S R - - 1991
The arterial wall proteoglycans play a crucial role in the pathogenesis of atherosclerosis as depicted schematically in Figure 7. Plasma components including lipoproteins cross the endothelium mainly by a non-specific bulk-phase vesicular transport. A selective interaction of apoB-containing lipoproteins occurs with proteoglycans of the subendothelial layer which results in extracellular ...
Goldberg A - - 1991
Cellular responses in bee venom (BV) allergy is a controversial issue. Previous studies could not reach an agreement whether this mechanism is activated as a result of allergic sensitization to bee venom. All previous works have used lymphocyte proliferation as their method to analyze cell-mediated immunity. In the present work, ...
Saini J S - - 1990
Varied manifestations of herpes simplex keratitis are postulated to be related to alterations or paucity of protective immune response to the virus. In this study lymphocyte subpopulations and macrophage inhibition factor (MIF) assay are investigated in herpes simplex keratitis. Active T-lymphocytes are detected to be significantly low in active keratitis ...
Fong L G - - 1990
In vitro, metabolism of modified forms of low density lipoprotein (LDL) by macrophages via the acetyl-LDL receptor pathway promotes the massive cellular accumulation of lipid. It has been postulated that in vivo this contributes to foam cell formation in the atherosclerotic lesion. Recent studies have shown that arterial wall cells ...
Cavaillon J M - - 1990
Recent evidence suggests that bacterial lipopolysaccharide binds to serum lipoproteins in vitro and in vivo and that lipopolysaccharide in the form that is bound to lipoprotein is less biologically active in several experimental models. In order to study the mechanism of this apparent detoxification, we compared the ability of free ...
Tertov V V - - 1990
Blood serum of most patients with coronary heart disease (CHD) caused a 2- to 5-fold increase in the lipid content of smooth muscle cells cultured from unaffected human aortic intima, i.e., possessed an atherogenic potential manifested in culture. Treatment of the CHD patients' serum with 2.5% polyethylene glycol 6000 removed ...
Ishibashi S - - 1990
We investigated the roles of lipoprotein lipase and apolipoprotein E (apoE) secreted from human monocyte-derived macrophages in the uptake of very low density lipoproteins (VLDL). ApoCII-deficient VLDL were isolated from a patient with apoCII deficiency. The lipolytic conversion to higher density and the degradation of the apoCII-deficient VLDL by macrophages ...
Faust R A - - 1990
Human macrophages in vitro synthesize and secrete the cholesteryl ester (CE) transfer protein, LTP-I. The effect of differentiation of monocyte-to-macrophage on the synthesis and secretion of LTP-I cholesteryl ester transfer activity was investigated. One marker of macrophage differentiation is expression of the 'scavenger' receptor, which mediates macrophage uptake and degradation ...
Frostegård J - - 1990
Hypercholesterolemia is a major risk factor for development of atherosclerosis. In experimental animals fed a high-cholesterol diet, monocytes adhere to the arterial endothelium and penetrate into the intima where they differentiate into macrophages and ingest lipids thus giving rise to fatty streaks, the earliest type of atherosclerotic plaque. Macrophages express ...
Kraemer F B - - 1990
The effects of activation on lipid and lipoprotein metabolism were examined in resident murine macrophages, inflammatory cells elicited by thioglycolate, primed cells elicited by pyran copolymer, and activated cells elicited by Corynebacterium parvum. Low density lipoprotein receptors were reduced by 70%, while scavenger receptors were reduced 60% in activated cells. ...
Singh S - - 1990
Candida albicans was found to repeatedly colonise and invade the duodenal ulcer base in a 45 years old otherwise healthy patient receiving H2 receptor antagonists for a prolonged period. He had no delayed hypersensitivity to Candida skin test, and had T cell deficiency, abnormality in T cell blast transformation, defective ...
Schwartz C J - - 1989
Atherosclerosis is conceptually defined as the result of a multiplicity of interactive cascades among injurious stimuli and the healing responses of the arterial wall, occurring concurrently within a hyperlipidemic environment. In this discussion, the inflammatory nature of the disease is emphasized. Four aspects of the pathophysiology of atherogenesis are addressed: ...
Khoo J C - - 1989
It was previously reported by Tabas et al. that J774 macrophages, unlike mouse peritoneal macrophages, accumulate large amounts of cholesteryl esters when incubated with native low-density lipoprotein (LDL). Comparison of the cell line (designated J774A.2) used in those experiments with its parent line (J774A.1) indicates that it is a variant ...
Rasmussen L T - - 1989
Human peritoneal macrophages were stimulated in vitro with beta-1,3-D-polyglucose-derivatized microbeads (GDM) or soluble aminated beta-1,3-D-polyglucose (AG) in combination with lipoproteins. The release of interleukin 1 (IL-1) was analysed in cell supernatants in a thymocyte proliferation assay. We report that the release of IL-1 is markedly enhanced in macrophages stimulated with ...
Simon M - - 1989
Synthesis of the Epstein-Barr virus (EBV) associated early antigen (EA) can be induced by a variety of agents in Raji cells, a latently EBV-infected Burkitt lymphoma line. We investigated the role of lipoproteins in this EA induction system. Cell growth was not affected by lipoprotein-deficiency, but EA induction by most ...
Gillissen G - - 1988
Antibiotics may influence immune response by quite different ways. By screening the multitude of publications on this subject, the aim of this overview was to arrive at a basic generalizing statement on the relationship between chemical structure or mode of action of antibiotics and the effect on immune response and ...
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