Using microparticle labeling and counting for attomole-level detection in heterogeneous immunoassay

Okano, Kazunori; Takahashi, Satoshi; Tokinaga, Daizo; Imai, Katsuyuki; Koga, Masashi

doi:10.1016/0003-2697(92)90217-u

Cited by 29 publications

(21 citation statements)

References 13 publications

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“…Plasma NO 2 Ϫ plus NO 3 Ϫ (NO X ) was measured by using an NO detector-HPLC system (ENO10; Eicom, Kyoto, Japan), as described (40). Plasma cGMP concentration was determined by specific RIA (RPN226, Amersham Pharmacia) (41).…”

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confidence: 99%

l -citrulline and l -arginine supplementation retards the progression of high-cholesterol-diet-induced atherosclerosis in rabbits

Hayashi

Juliet

Matsui-Hirai

et al. 2005

Proc. Natl. Acad. Sci. U.S.A.

131

117

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The objective of this study was to evaluate the influence of ingested L-arginine, L-citrulline, and antioxidants (vitamins C and E) on the progression of atherosclerosis in rabbits fed a highcholesterol diet. The fatty diet caused a marked impairment of endothelium-dependent vasorelaxation in isolated thoracic aorta and blood flow in rabbit ear artery in vivo, the development of atheromatous lesions and increased superoxide anion production in thoracic aorta, and increased oxidation-sensitive gene expression [Elk-1 and phosphorylated cAMP response element-binding protein]. Rabbits were treated orally for 12 weeks with L-arginine, L-citrulline, and͞or antioxidants. L-arginine plus L-citrulline, either alone or in combination with antioxidants, caused a marked improvement in endothelium-dependent vasorelaxation and blood flow, dramatic regression in atheromatous lesions, and decrease in superoxide production and oxidation-sensitive gene expression. These therapeutic effects were associated with concomitant increases in aortic endothelial NO synthase expression and plasma NO 2 ؊ ؉ NO 3 ؊ and cGMP levels. These observations indicate that ingestion of certain NO-boosting substances, including L-arginine, L-citrulline, and antioxidants, can abrogate the state of oxidative stress and reverse the progression of atherosclerosis. This approach may have clinical utility in the treatment of atherosclerosis in humans.antioxidant ͉ nitric oxide ͉ amino acids ͉ endothelial nitric oxide synthase A therosclerosis is an inflammatory disease (1) characterized by vascular endothelial cell dysfunction and diminished production of NO (2-5). Endothelial NO synthase (eNOS) gene transfer can reduce atherogenesis in hypercholesterolemic animals (6). NO is a widespread signaling molecule in the cardiovascular system, which functions in multiple ways to protect against the initiation and progression of atherosclerosis (7-9). For example, NO aids in preventing the adhesion and aggregation of blood cells and platelets along the endothelial cell lining in blood vessels (7,8) and is a potent inhibitor of vascular smooth muscle cell proliferation (10). NO is a potent antioxidant that can elicit antiinflammatory effects by scavenging certain reactive oxygen species (11-13), and it can prevent the oxidation of low-density lipoprotein cholesterol and thereby retard the progression of atherosclerosis (5, 14). Moreover, NO deficiency is generally associated with up-regulation of oxidation-sensitive genes, whereas increased NO production leads to decreased expression of oxidation-sensitive genes (7,15). NO is synthesized by NOS, which utilizes L-arginine as substrate and produces L-citrulline as the second reaction product. L-arginine can be synthesized from L-citrulline in endothelial and other cell types, thereby providing a recycling pathway for the conversion of L-citrulline to NO via L-arginine (16)(17)(18)(19).The oral administration of L-arginine to animals (7, 12, 20-26) and humans (5,8,(27)(28)(29) has been demonstrated to slow the progressi...

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mentioning

confidence: 99%

l -citrulline and l -arginine supplementation retards the progression of high-cholesterol-diet-induced atherosclerosis in rabbits

Hayashi

Juliet

Matsui-Hirai

et al. 2005

Proc. Natl. Acad. Sci. U.S.A.

131

117

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“…Detection in these "biosensors" requires direct differential labeling of multiple antigens (multiplexing), which renders the use of enzyme labels difficult. Radioimmunoassays (RIAs) 2 give direct and generally sensitive results, but have important disadvantages-in addition to the lack of extensive multiplexing capabilities, there is a trend away from using radioisotopes because of ecological, safety, and economic constraints. Therefore, efforts have been made to establish direct-detection immunoassays exhibiting high sensitivity.…”

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confidence: 99%

“…One of these direct, highly sensitive immunoassays uses microparticle labeling methodology with visual counting of labeled antigen (2). Although this methodology is very sensitive (the limit of detection for human ␣-fetoprotein is 1.9 ϫ 10 7 molecules/ml), the detection process is time-consuming and cumbersome.…”

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confidence: 99%

High Sensitivity Immunoassays Using Particulate Fluorescent Labels

Hall

Kazakova

Yao

1999

Analytical Biochemistry

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“…These microbeads bearing rat anti-mouse IgG1 monoclonal antibody (mAb) (Pharmingen, San Diego, CA, USA), covalently coupled to the bead by the carbodiimide method [6] (control beads), were used for control experiments. Identically prepared beads were then incubated with anti-human CD18 mAb (isotype: mouse IgG1; Endogen, Woburn, MA, USA), and these (denoted anti-CD18 beads) were used for test experiments.…”

Section: Bead Preparationmentioning

confidence: 99%

Interaction of non-adherent suspended neutrophils to complement opsonized pathogens: a new assay using optical traps

et al. 2006

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Phagocytosis of opsonized pathogens by circulating non-adherent neutrophils is an essential step in host defense, which when overwhelmed contributes to sepsis. To investigate the role played by ligation of complement receptors CR3 and CR4 in non-adherent neutrophils, we designed a novel assay system utilizing dual optical traps, respectively, holding a suspended unactivated cell and presenting a specific ligand-coated bead to the cell surface. We chose anti-CD18 as an example ligand, mimicking the bacterial opsonizing complement fragment iC3b. Presentation of anti-CD18-coated beads elicited both pseudopodial protrusion and subsequent phagocytosis. This is in sharp contrast to previously reported responses of adherent neutrophils, which phagocytize opsonized particles without pseudopod formation. We used this same new assay to probe actomyosin pathways in the neutrophil's pseudopodial and phagocytic response. Disruption of actin or inhibition of myosin light-chain kinase dose-dependently reduced pseudopod formation and phagocytosis rates. In summary, i) the new dual trap assay can be used to study the responses of suspended neutrophils to a variety of ligands, and ii) in a first application of this technique, we found that local ligation of CR3/4 in unactivated neutrophils in suspension induces pseudopod formation and phagocytosis at that site, and that these events occur via an actomyosindependent pathway.

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Using microparticle labeling and counting for attomole-level detection in heterogeneous immunoassay

Cited by 29 publications

References 13 publications

l -citrulline and l -arginine supplementation retards the progression of high-cholesterol-diet-induced atherosclerosis in rabbits

l -citrulline and l -arginine supplementation retards the progression of high-cholesterol-diet-induced atherosclerosis in rabbits

High Sensitivity Immunoassays Using Particulate Fluorescent Labels

Interaction of non-adherent suspended neutrophils to complement opsonized pathogens: a new assay using optical traps

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