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Pownall HJ, Liu J, Gillard BK, Yelamanchili D, Rosales C. Physico-chemical and physiological determinants of lipo-nanoparticle stability. NANOMEDICINE-NANOTECHNOLOGY BIOLOGY AND MEDICINE 2021; 33:102361. [PMID: 33540069 DOI: 10.1016/j.nano.2021.102361] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/24/2020] [Revised: 12/31/2020] [Accepted: 01/07/2021] [Indexed: 12/18/2022]
Abstract
Liposome-based nanoparticles (NPs) comprised mostly of phospholipids (PLs) have been developed to deliver diagnostic and therapeutic agents. Whereas reassembled plasma lipoproteins have been tested as NP carriers of hydrophobic molecules, they are unstable because the components can spontaneously transfer to other PL surfaces-cell membranes and lipoproteins-and can be degraded by plasma lipases. Here we review two strategies for NP stabilization. One is to use PLs that contain long acyl-chains: according to a quantitative thermodynamic model and in vivo tests, increasing the chain length of a PL reduces the spontaneous transfer rate and increases plasma lifetime. A second strategy is to substitute ether for ester bonds which makes the PLs lipase resistant. We conclude with recommendations of simple ex vivo and in vitro tests of NP stability that should be conducted before in vivo tests are begun.
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Affiliation(s)
- Henry J Pownall
- Center for Bioenergetics, Department of Medicine, Houston Methodist Academic Institute, Houston, TX, USA; Weill Cornell Medicine, New York, NY, USA.
| | - Jing Liu
- Center for Bioenergetics, Department of Medicine, Houston Methodist Academic Institute, Houston, TX, USA; Department of Cardiovascular Medicine, Xiangya Hospital, Central South University, Changsha, China
| | - Baiba K Gillard
- Center for Bioenergetics, Department of Medicine, Houston Methodist Academic Institute, Houston, TX, USA; Weill Cornell Medicine, New York, NY, USA
| | - Dedipya Yelamanchili
- Center for Bioenergetics, Department of Medicine, Houston Methodist Academic Institute, Houston, TX, USA
| | - Corina Rosales
- Center for Bioenergetics, Department of Medicine, Houston Methodist Academic Institute, Houston, TX, USA; Weill Cornell Medicine, New York, NY, USA
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2
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KINOSHITA M, MATSUSHIMA T, MASHIMO Y, KOJIMA M, KIGURE M, TERAMOTO T. Determination of Immuno-Reactive Rabbit Apolipoprotein B-48 in Serum by ELISA. Exp Anim 2010; 59:459-67. [DOI: 10.1538/expanim.59.459] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Affiliation(s)
- Makoto KINOSHITA
- Department of Internal Medicine, Teikyo University School of Medicine
| | | | - Yamato MASHIMO
- Department of Internal Medicine, Teikyo University School of Medicine
| | | | | | - Tamio TERAMOTO
- Department of Internal Medicine, Teikyo University School of Medicine
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3
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Li CM, Presley JB, Zhang X, Dashti N, Chung BH, Medeiros NE, Guidry C, Curcio CA. Retina expresses microsomal triglyceride transfer protein: implications for age-related maculopathy. J Lipid Res 2005; 46:628-40. [PMID: 15654125 DOI: 10.1194/jlr.m400428-jlr200] [Citation(s) in RCA: 72] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The principal extracellular lesions of age-related maculopathy (ARM), the leading cause of vision loss in the elderly, involve Bruch's membrane (BrM), a thin vascular intima between the retinal pigment epithelium (RPE) and its blood supply. With age, 80-100 nm solid particles containing esterified cholesterol (EC) accumulate in normal BrM, and apolipoprotein B (apoB) immunoreactivity is detectable in BrM- and ARM-associated lesions. Yet little evidence indicates that increased plasma cholesterol is a risk factor for ARM. To determine if RPE is capable of assembling its own apoB-containing lipoprotein, we examined RPE for the expression of microsomal triglyceride transfer protein (MTP), which is required for this process. Consistent with previous evidence for apoB expression, MTP is expressed in RPE, the ARPE-19 cell line, and, unexpectedly, retinal ganglion cells, which are neurons of the central nervous system. De novo synthesis and secretion of neutral lipid by ARPE-19 was supported by high levels of radiolabeled EC and triglyceride in medium after supplementation with oleate. Lipoprotein assembly and secretion is implicated as a constitutive retinal function and a plausible candidate mechanism involved in forming extracellular cholesterol-containing lesions in ARM. The pigmentary retinopathy and neuropathy of abetalipoproteinemia (Mendelian Inheritance of Man 200100; Bassen-Kornzwieg disease), which is caused by mutations in the MTP gene, may involve loss of function at the retina.
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Affiliation(s)
- Chuan-Ming Li
- Department of Ophthalmology, University of Alabama School of Medicine, Birmingham, AL, USA
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4
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Kinoshita M, Kojima M, Matsushima T, Teramoto T. Determination of apolipoprotein B-48 in serum by a sandwich ELISA. Clin Chim Acta 2005; 351:115-20. [PMID: 15563879 DOI: 10.1016/j.cccn.2004.08.008] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2004] [Revised: 08/17/2004] [Accepted: 08/17/2004] [Indexed: 11/22/2022]
Abstract
BACKGROUND Apolipoprotein B-48 (apoB-48) is produced by the small intestine, as a part of chylomicrons (CMs), and appears to be a suitable marker for clinical studies of postprandial lipoproteins and related cardiovascular risk factors. We have developed an assay for routine analysis to quantify apoB-48 in serum or plasma. METHODS A microtiter plate was coated with monoclonal antibody (4C8) raised against apoB-48 C-terminal specific decapeptide. Serum samples were diluted 100-fold with 0.05 mol/l Tris-HCl buffer (with or without 0.1% Triton X-100). Appropriate calibration curves were obtained in the ELISA by using apoB-48 recombinant antigen. RESULTS No cross-reactivity (<0.001%) was found with apoB-100, as verified by ELISA and Western blot analyses. Intra- and inter-assay CVs were 4.8% and 5.4%, respectively. Recovery of added recombinant apoB-48 in serum was within 94-105%. The assay linearity was intact >5-fold dilution of serum by dilution buffer. ApoB-48 levels in healthy controls (n=18) at fasting were within the range of 2.69-6.56 microg/ml (mean+/-S.D.: 4.60+/-1.54 microg/ml). In healthy subjects, serum apoB-48 concentrations markedly increased in the postprandial state, in parallel with serum triglycerides. CONCLUSION This method for measuring apoB-48 using the monoclonal antibody 4C8 is simple, reliable and suitable for routine analyses.
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Affiliation(s)
- Makoto Kinoshita
- Department of Internal Medicine, Teikyo University School of Medicine, Itabashi, Tokyo 173-8605 Japan.
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5
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Smart EJ, Anderson RGW. Alterations in membrane cholesterol that affect structure and function of caveolae. Methods Enzymol 2002; 353:131-9. [PMID: 12078489 DOI: 10.1016/s0076-6879(02)53043-3] [Citation(s) in RCA: 104] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Most of the available methods for modifying caveolae structure and function depend on altering the cholesterol content of caveolae. The most important aspect of each method is to ensure the reagents are working in the cells that are being studied. The idiosyncrasies of each method are such that they cannot be universally applied without carefully optimizing the conditions. When used correctly, these methods are accepted as a specific way to perturb the structure and function of caveolae.
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Affiliation(s)
- Eric J Smart
- Department of Physiology, University of Kentucky Medical School, Lexington, Kentucky 40536, USA
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6
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Amin K, Wasan KM, Albrecht RM, Heath TD. Cell association of liposomes with high fluid anionic phospholipid content is mediated specifically by LDL and its receptor, LDLr. J Pharm Sci 2002; 91:1233-44. [PMID: 11977099 DOI: 10.1002/jps.10075] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
We have sought to confirm indications in our recent studies suggesting that association of liposomes composed of 75-100 mol % egg phosphatidylglycerol (ePG), a fluid anionic phospholipid, with cells is mediated by low density lipoprotein (LDL) and the classical LDL receptor (LDLr). In the present study, binding of liposomes composed of 75-100 mol % ePG to CV1-P cells, either in serum-supplemented medium or in defined medium supplemented with LDL, is blocked by the presence of either of two monoclonal antibodies. The first is immunoglobulin (Ig)G C7, an antibody specific for LDLr. The second is IgG 5E11, an antibody specific for domain 3441-3569 of apolipoprotein B100. CHOldlA7, a cell line known to lack the LDLr and previously shown by us to associate minimally with 75-100 mol % ePG liposomes, was transfected with the human LDLr. The transfected cells bound 75-100 mol % ePG liposomes at high levels, and this binding was blocked by IgG C7. Previously, we have shown that serum, but not LDL or high density lipoprotein, induces association of 25-50 mol % ePG liposomes with both CV1-P and CHO wild type cells, but not CHOldlA7. In the present study, IgG C7 does not block this interaction, and transfected CHOldlA7 cells do not show this interaction. Hence, this form of liposome binding appears not to involve LDL or LDLr, but requires a receptor, currently unknown, and a serum component other than LDL or high density lipoprotein. The unknown receptor, in addition to LDLr, is missing from CHOldlA7.
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Affiliation(s)
- Ketan Amin
- Department of Pharmaceutics, School of Pharmacy, University of Wisconsin-Madison, 777 Highland Avenue, Madison, WI 53705-2222, USA
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7
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On-Site diagnostic device based on immuno-separation of proteins. KOREAN J CHEM ENG 2001. [DOI: 10.1007/bf02698469] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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8
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Lorec AM, Juhel C, Pafumi Y, Portugal H, Pauli AM, Lairon D, Defoort C. Determination of Apolipoprotein B-48 in Plasma by a Competitive ELISA. Clin Chem 2000. [DOI: 10.1093/clinchem/46.10.1638] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
AbstractBackground: Apolipoprotein B-48 (apoB-48) is produced by the small intestine, as part of chylomicrons, and appears to be a suitable marker for clinical studies of postprandial lipoproteins and related cardiovascular risk. Our aim was to develop, for routine analysis, an assay to quantify apoB-48 in plasma samples.Methods: A microtiter plate was coated with a C-terminal apoB-48-specific heptapeptide. Plasma samples were incubated with appropriate detergent to allow competition between immobilized antigen and plasma apoB-48. Appropriate calibration curves were obtained in the ELISA, using calibrated lymph and chylomicrons.Results: Treatment of plasma samples with the mild detergent Triton X-100 allowed an efficient competition between immobilized antigen and plasma apoB-48. No cross-reactivity was found with apoB-100, as checked by ELISA and Western blot analysis. Intra- and interassay CVs were 5.4% and 5.5%, respectively. In healthy subjects, apoB-48 concentrations markedly increased in the postprandial state, in parallel with triglycerides.Conclusions: This new ELISA allows determination of the concentration of apoB-48 in normolipidemic plasma.
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Affiliation(s)
- Anne-Marie Lorec
- Laboratoire Central, Hôpital Sainte-Marguerite, 270 Bd Sainte-Marguerite BP 29, 13274 Marseille Cedex 09, France
| | - Christine Juhel
- Unité INSERM 476, 18 Avenue Mozart, 13009 Marseille, France
| | - Yan Pafumi
- Unité INSERM 476, 18 Avenue Mozart, 13009 Marseille, France
| | - Henri Portugal
- Laboratoire Central, Hôpital Sainte-Marguerite, 270 Bd Sainte-Marguerite BP 29, 13274 Marseille Cedex 09, France
- Laboratoire de Chimie Analytique, Faculté de Pharmacie, 27 Bd J Moulin, 13005 Marseille, France
| | - Anne-Marie Pauli
- Laboratoire de Chimie Analytique, Faculté de Pharmacie, 27 Bd J Moulin, 13005 Marseille, France
| | - Denis Lairon
- Unité INSERM 476, 18 Avenue Mozart, 13009 Marseille, France
| | - Catherine Defoort
- Unité INSERM 476, 18 Avenue Mozart, 13009 Marseille, France
- Laboratoire de Chimie Analytique, Faculté de Pharmacie, 27 Bd J Moulin, 13005 Marseille, France
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Uittenbogaard A, Shaul PW, Yuhanna IS, Blair A, Smart EJ. High density lipoprotein prevents oxidized low density lipoprotein-induced inhibition of endothelial nitric-oxide synthase localization and activation in caveolae. J Biol Chem 2000; 275:11278-83. [PMID: 10753938 DOI: 10.1074/jbc.275.15.11278] [Citation(s) in RCA: 258] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Oxidized LDL (oxLDL) depletes caveolae of cholesterol, resulting in the displacement of endothelial nitric-oxide synthase (eNOS) from caveolae and impaired eNOS activation. In the present study, we determined if the class B scavenger receptors, CD36 and SR-BI, are involved in regulating nitric-oxide synthase localization and function. We demonstrate that CD36 and SR-BI are expressed in endothelial cells, co-fractionate with caveolae, and co-immunoprecipitate with caveolin-1. Co-incubation of cells with 10 microgram/ml high density lipoprotein (HDL) prevented oxLDL-induced translocation of eNOS from caveolae and restored acetylcholine-induced nitric-oxide synthase stimulation. Acetylcholine caused eNOS activation in cells incubated with 10 microgram/ml oxLDL (10-15 thiobarbituric acid-reactive substances) and blocking antibodies to CD36, whereas cells treated with only oxLDL were unresponsive. Furthermore, CD36-blocking antibodies prevented oxLDL-induced redistribution of eNOS. SR-BI-blocking antibodies were used to demonstrate that the effects of HDL are mediate by SR-BI. HDL binding to SR-BI maintained the concentration of caveola-associated cholesterol by promoting the uptake of cholesterol esters, thereby preventing oxLDL-induced depletion of caveola cholesterol. We conclude that CD36 mediates the effects of oxLDL on caveola composition and eNOS activation. Furthermore, HDL prevents oxLDL from decreasing the capacity for eNOS activation by preserving the cholesterol concentration in caveolae and, thereby maintaining the subcellular location of eNOS.
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Affiliation(s)
- A Uittenbogaard
- Department of Physiology, University of Kentucky Medical School, Lexington, Kentucky 40536, USA
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10
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Blair A, Shaul PW, Yuhanna IS, Conrad PA, Smart EJ. Oxidized low density lipoprotein displaces endothelial nitric-oxide synthase (eNOS) from plasmalemmal caveolae and impairs eNOS activation. J Biol Chem 1999; 274:32512-9. [PMID: 10542298 DOI: 10.1074/jbc.274.45.32512] [Citation(s) in RCA: 264] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Hypercholesterolemia-induced vascular disease and atherosclerosis are characterized by a decrease in the bioavailability of endothelium-derived nitric oxide. Endothelial nitric-oxide synthase (eNOS) associates with caveolae and is directly regulated by the caveola protein, caveolin. In the present study, we examined the effects of oxidized low density lipoprotein (oxLDL) on the subcellular location of eNOS, on eNOS activation, and on caveola cholesterol in endothelial cells. We found that treatment with 10 microgram/ml oxLDL for 60 min caused greater than 90% of eNOS and caveolin to leave caveolae. Treatment with oxLDL also inhibited acetylcholine-induced activation of eNOS but not prostacyclin production. oxLDL did not affect total cellular eNOS abundance. Oxidized LDL also did not affect the palmitoylation, myristoylation or phosphorylation of eNOS. Oxidized LDL, but not native LDL, or HDL depleted caveolae of cholesterol by serving as an acceptor for cholesterol. Cyclodextrin also depleted caveolae of cholesterol and caused eNOS and caveolin to translocate from caveolae. Furthermore, removal of oxLDL allowed eNOS and caveolin to return to caveolae. We conclude that oxLDL-induced depletion of caveola cholesterol causes eNOS to leave caveolae and inhibits acetylcholine-induced activation of the enzyme. This process may be an important mechanism in the early pathogenesis of atherosclerosis.
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Affiliation(s)
- A Blair
- Department of Physiology, University of Kentucky Medical School, Lexington, Kentucky 40536, USA
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11
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Kruth HS, Chang J, Ifrim I, Zhang WY. Characterization of patocytosis: endocytosis into macrophage surface-connected compartments. Eur J Cell Biol 1999; 78:91-9. [PMID: 10099931 DOI: 10.1016/s0171-9335(99)80010-7] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022] Open
Abstract
Previously, we described a unique macrophage endocytosis pathway in which aggregated low density lipoproteins and microcrystalline cholesterol induce and enter a labyrinth of membrane-bound compartments that remain connected to the cell surface. We now show that certain types of non-lipid particles such as polystyrene microspheres and colloidal gold also induce and enter macrophage surface-connected compartments (SCC), a process we call patocytosis. A common property among particles that stimulate patocytosis is their hydrophobic nature. Both aggregated LDL and microcrystalline cholesterol that we showed previously to stimulate patocytosis are hydrophobic. We now show that hydrophobic polystyrene microspheres and gold particles but not their hydrophilic counterparts triggered patocytosis. Uptake by patocytosis was limited to hydrophobic polystyrene microsphere particles less than 0.5 micron in diameter. Hydrophobic polystyrene microspheres greater than this size entered macrophages by phagocytosis. Actin-independent capping of hydrophobic polystyrene microspheres on the plasma membrane preceded actin-dependent uptake of the microspheres into SCC. Sequential rounds of microsphere uptake into SCC over two successive days could occur. There was some mixing of initial and subsequently accumulated microspheres in SCC. SCC formed from plasma membrane invaginations that connected with spaces created by unfolding of stacks of internal microvilli. Microsphere transport from plasma membrane invaginations into these spaces was inhibited by primaquine. Patocytosis is a unique endocytic process in macrophages triggered by small hydrophobic particles that provides a mechanism to sequester large amounts of these materials within a labyrinth of SCC.
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Affiliation(s)
- H S Kruth
- Section of Experimental Atherosclerosis, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892-1422, USA.
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12
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Paek SH, Jang MR, Mok RS, Kim SC, Kim HB. Immunochromatographic membrane strip assay system for a single-class plasma lipoprotein cholesterol, exemplified by high-density lipoprotein cholesterol measurement. Biotechnol Bioeng 1999; 62:145-54. [PMID: 10099523 DOI: 10.1002/(sici)1097-0290(19990120)62:2<145::aid-bit3>3.0.co;2-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
In assessing risk factors of coronary heart disease, a membrane immunochromatographic system that minimizes requirements of instrument and reagent handling was investigated by utilizing high-density lipoprotein (HDL) cholesterol (HDL-C) as model analyte. The system is composed of four functional membrane strip pads connected in sequence as follows (from the bottom): immunoseparation based on the biotin-streptavidin reaction; catalytic conversion of cholesterol to hydrogen peroxide; production of a colorimetric signal; and induction of a continuous wicking of medium. For immunochromatography, a monoclonal antibody, specific to apolipoprotein B100 that is present on the surfaces of low-density lipoproteins (LDL) and very low-density lipoproteins (VLDL), with a high binding constant (5 x 10(10) L/mol), was raised and chemically conjugated to streptavidin. The conjugate was first reacted with lipoprotein particles, and this mixture was absorbed by the capillary action into the biotin pad of the system. After being transferred by medium, immunocapture of LDL and VLDL particles onto the biotin pad took place, and in situ generation of a colorimetric signal in proportion to HDL-C occurred consecutively. The capture was selective as well as effective (minimum 88% of LDL and VLDL in clinical concentration ranges), and the detection limit of the HDL-C was far lower than 20 mg per 100 mL. The same concept may also be applicable to LDL cholesterol measurement provided suitable antibodies specific to HDL and VLDL are available.
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Affiliation(s)
- S H Paek
- Graduate School of Biotechnology, Korea University, Seoul 136-701,
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13
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Coussons PJ, Bourgeois CS, Wiggins D, Gibbons GF. Selective recruitment of ApoB-48 for the assembly of VLDL in rat triacylglycerol-enriched hepatocytes. Arterioscler Thromb Vasc Biol 1996; 16:889-97. [PMID: 8673565 DOI: 10.1161/01.atv.16.7.889] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Primary rat hepatocyte cultures were enriched in cellular triacylglycerol (TAG) by exposure to extracellular oleate for 3 days. Control cells were cultured for the same time without oleate. The large increase in TAG secretion into the medium of TAG-enriched cells during the final 24 hours (225 +/- 30 versus 40 +/- 10 micrograms/mg cell protein [control cells], P < .01) was not accompanied by a similar change in apolipoprotein B (apoB) secretion (4.22 +/- 0.94 versus 3.72 +/- 0.75 micrograms/mg per 24 hours, respectively). Instead, TAG-enriched cells recruited a larger proportion of apoB for the synthesis of very low density lipoprotein (VLDL), the secretion of which was substantially higher under these circumstances (1.46 +/- 0.39 versus 0.34 +/- 0.06 microgram apoB per milligram cell protein per 24 hours, P < .05). The increase in VLDL assembly was accompanied by a selective 2.5-fold increase (P < .05) in the specific recruitment of apoB-48. There was no significant increase in the amount of apoB-100, which appeared in the VLDL fraction when cells were enriched with TAG. Under these circumstances there was an increase in net cellular synthesis of apoB-48 (5524 +/- 667 versus 2505 +/- 598 disintegrations per minute per milligram protein per hour, P < .05). The net cellular synthesis of apoB-100 was unchanged compared with that observed in control cell cultures (1548 +/- 237 versus 2000 +/- 897 dpm/ mg per hour, respectively). A large proportion of the total secreted apoB was associated with small particles of density higher than VLDL, even when VLDL output was maximally stimulated, suggesting that apoB was oversecreted and in excess of the cells' requirement to transport TAG.
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Affiliation(s)
- P J Coussons
- Oxford Lipid Metabolism Group, Nuffield Department of Clinical Medicine, University of Oxford, Radcliffe Infirmary, UK
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14
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Chatterton JE, Schlapfer P, Bütler E, Gutierrez MM, Puppione DL, Pullinger CR, Kane JP, Curtiss LK, Schumaker VN. Identification of apolipoprotein B100 polymorphisms that affect low-density lipoprotein metabolism: description of a new approach involving monoclonal antibodies and dynamic light scattering. Biochemistry 1995; 34:9571-80. [PMID: 7626627 DOI: 10.1021/bi00029a034] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Rare mutations in apolipoprotein B (apoB) can cause defective binding of low-density lipoproteins (LDLs) to the LDL receptor, leading to elevated plasma cholesterol levels and premature atherosclerosis. This communication describes a novel approach to study the effects of apoB mutations on LDL metabolism. Monoclonal antibody MB19 identifies a common polymorphism in apoB, an Ile/Thr substitution at residue 71, by binding with a 60-fold higher affinity to apoB(Ile71)-containing LDL. Because each LDL contains a single apoB, a maximum of two LDLs may be bound by the bivalent monoclonal antibody. Thus, at the appropriate concentration, an equivalent amount of MB19 will promote substantial dimer formation of LDL containing the strongly binding apoB(Ile71), but little dimer formation of LDL containing the weakly binding apoB(Thr71). For LDL isolated from heterozygous individuals, the amount of dimer formed, determined by dynamic light scattering, yields an estimate of the allelic ratio of the two forms of LDL. For such individuals, not only the effect of the polymorphism recognized by MB19 but also the effects of other polymorphisms on the LDL allelic ratio can be determined. Examination of six normolipemic MB19 heterozygotes gave percent allelic ratios between 48:52 and 51:49 tight:weak-binding LDL, not significantly different from a 50:50 ratio. These individuals were also heterozygous for six common apoB polymorphisms, allowing calculation of the odds that each of these polymorphisms caused significant alterations in lipid levels. In contrast, the rare mutation at residue 3500 causing defective binding to the LDL receptor and familial defective apoB100 (FDB) resulted in substantial changes (26:74 and 13:87) in LDL allelic ratio in both of two FDB individuals examined.
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Affiliation(s)
- J E Chatterton
- Department of Chemistry and Biochemistry, University of California, Los Angeles 90024, USA
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15
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Duerden JM, Gibbons GF. Restoration in vitro of normal rates of very-low-density lipoprotein triacylglycerol and apoprotein B secretion in hepatocyte cultures from diabetic rats. Biochem J 1993; 294 ( Pt 1):167-71. [PMID: 8363568 PMCID: PMC1134580 DOI: 10.1042/bj2940167] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Hepatocytes derived from diabetic rats were cultured in serum-free Waymouth's medium containing various supplements, after an initial 4 h period during which the cells were allowed to attach to the culture dish in the presence of foetal-bovine serum (10%). After removal of serum, these cells secreted much less very-low-density lipoprotein (VLDL) apoprotein B (apoB) and triacylglycerol than those derived from normal rats when cultured for 24 h in the basal medium. Inclusion of oleate (0.75 mM) in the medium initially increased the output of apoB and triacylglycerol, but the rates remained lower than those observed in normal hepatocytes and declined to zero after 72 h. This time-dependent decline in VLDL output was prevented by addition of dexamethasone to the oleate-containing medium. Levels of apoB and triacylglycerol output characteristic of normal hepatocytes could only be completely restored, however, by further addition of a mixture of lipogenic substrates (lactate plus pyruvate) to the medium. Restoration of normal levels of VLDL secretion in diabetic hepatocytes in vitro by this means was accompanied by a normal inhibitory response of apoB and triacylglycerol output to short-term (24 h) treatment with insulin or glucagon. Exposure of the cells to insulin for 72 h enhanced the secretion of VLDL, whereas treatment with glucagon for the same period potentiated the original inhibitory effect. The defective secretion of VLDL apoB observed when diabetic hepatocytes were cultured in the basal medium for 24 h could also be rectified by inclusion of a mixture of oleate (0.75 mM), lactate (10 mM), pyruvate (1 mM), dexamethasone (1 microM) and insulin (78 nM) in the medium during the 4 h attachment period in the presence of serum. Under these conditions, the increase in the secretory response of triacylglycerol was not so pronounced.
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Affiliation(s)
- J M Duerden
- Nuffield Department of Clinical Medicine, University of Oxford, Radcliffe Infirmary, U.K
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16
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Esfahani M, Bigler RD, Alfieri JL, Lund-Katz S, Baum JD, Scerbo L. Cholesterol regulates the cell surface expression of glycophospholipid-anchored CD14 antigen on human monocytes. BIOCHIMICA ET BIOPHYSICA ACTA 1993; 1149:217-23. [PMID: 7686772 DOI: 10.1016/0005-2736(93)90204-d] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The CD14 antigen which is expressed on human monocytes and macrophages is a phosphatidylinositol-linked surface protein. We investigated the effects of cellular cholesterol depletion and repletion on cell surface expression of this glycoprotein. Adherent normal human monocytes were cultured for four days in media containing delipidated fetal calf serum which depleted cellular cholesterol. Immunofluorescence analysis demonstrated a markedly diminished surface expression of CD14 on cells cultured in delipidated serum compared to normal serum. Expression of CD64 (high-affinity Fc receptors, Fc gamma RI) also was reduced under these conditions. This inhibition of CD14 expression was overcome by addition to the culture medium of cholesterol, low density lipoprotein, or very low density lipoprotein. All of these supplements replenished cellular cholesterol. Expression of CD64(Fc gamma RI) was not restored by addition of cholesterol. These observations indicate that cholesterol can regulate the surface expression of some phosphatidylinositol-anchored glycoproteins.
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Affiliation(s)
- M Esfahani
- Department of Biological Chemistry, Hahnemann University School of Medicine, Philadelphia, PA 19102-1192
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Abstract
Systemic lupus erythematosus (SLE) sera, two classes of serum lipoproteins, and IgG antibodies from SLE and normal sera were tested for their reactivity with a Z-DNA polymer, Br-poly (dG-dC). In all cases preferential binding to Z-DNA over B-DNA was observed. This interaction, for the most part, could be inhibited by the negatively charged phospholipid, cardiolipin, which suggests that most of the anti-Z-DNA activity associated with sera arises from relatively non-specific ionic interactions between proteins and polyanionic molecules. An assay has been described that can eliminate proteins cross-reactive with negatively charged phospholipids.
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Affiliation(s)
- P Krishna
- Department of Medical Biochemistry, University of Calgary, Alberta, Canada
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18
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Gugliucci Creriche A, Stahl AJ. Glycation and oxidation of human low density lipoproteins reduces heparin binding and modifies charge. Scand J Clin Lab Invest 1993; 53:125-32. [PMID: 8469911 DOI: 10.3109/00365519309088399] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
The effects of glycation and oxidation of human low density lipoproteins (LDL) on heparin binding were studied and compared with modifications in the charge of the particles. Glycation of LDL at a molar ratio of 4 mol glucose mol-1 apoB, decreases affinity for heparin, as shown by heparin-agarose affinity chromatography since salt molarity needed for elution decreases from 550 mmol l-1 for control LDL (c-LDL) to 350 mmol l-1 for glycated LDL (glc-LDL). Oxidized LDL (oxi-LDL) shows marked heterogeneity, most of the fractions having decreased affinity. Heparin-agarose affinity chromatography of LDL preparations shows the presence of a small (5-7%), low-affinity fraction in euglycaemic human plasma LDL (c-LDL). Its elution volume coincides with both glc-LDL and a fraction of oxi-LDL, suggesting it may contain glycated and oxidized molecules present in plasma. DEAE-Trisacryl anion exchange chromatography elution profiles of c-LDL preparations shows the presence of a more electronegative fraction accounting for about 10% of total protein. This fraction elutes with 260 mmol l-1 NaCl instead of 130 mmol l-1 for the main fraction, it roughly coincides with elution volumes of main peaks of glc-LDL and oxi-LDL. Results indicate that glycated particles may be present in this fraction. Our data demonstrate then that glycation, and to a lesser degree, oxidation of LDL reduce affinity to heparin. From an analytical approach, modified LDL can be separated from the bulk of native LDL both by DEAE and heparin-agarose chromatographies.(ABSTRACT TRUNCATED AT 250 WORDS)
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19
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Higuchi K, Kitagawa K, Kogishi K, Takeda T. Developmental and age-related changes in apolipoprotein B mRNA editing in mice. J Lipid Res 1992. [DOI: 10.1016/s0022-2275(20)41333-1] [Citation(s) in RCA: 58] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
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20
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Chuck SL, Lingappa VR. Pause transfer: a topogenic sequence in apolipoprotein B mediates stopping and restarting of translocation. Cell 1992; 68:9-21. [PMID: 1370657 DOI: 10.1016/0092-8674(92)90202-n] [Citation(s) in RCA: 104] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Previously, we described the stepwise translocation of a large amino-terminal fragment of apolipoprotein B (apo B15) in which the nascent secretory chain translocates through a series of distinct, nonintegrated transmembrane intermediates with large domains exposed to the cytoplasm. Thus, apo B15 appears to stop and restart translocation at several points. We have identified a sequence of amino acids in apo B15 that confers this behavior on a heterologous chimeric protein. In addition, we dissect pausing into two distinct steps, stopping and restarting, thereby trapping otherwise transient intermediates. Finally, we demonstrate the function of a second "pause transfer" sequence over 200 amino acids downstream in apo B15 that restarts translocation posttranslationally, suggesting that multiple pause transfer sequences are involved in the biogenesis of apolipoprotein B.
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Affiliation(s)
- S L Chuck
- Department of Microbiology and Immunology, University of California, San Francisco 94143-0444
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21
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Gugliucci Creriche A, Dumont S, Siffert JC, Stahl AJ. In vitro glycated low-density lipoprotein interaction with human monocyte-derived macrophages. RESEARCH IN IMMUNOLOGY 1992; 143:17-23. [PMID: 1314405 DOI: 10.1016/0923-2494(92)80075-v] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Human low-density lipoprotein (LDL) was glycated in vitro (5 days, glucose 50 mmol/l), labelled with 125I, and its binding and uptake by human monocyte-derived macrophages studied. Glycation produced lower binding and lower uptake. Competition experiments using unlabelled LDL (control, glycated, and acetyl-LDL) showed that most glycated LDL was taken up by the apolipoprotein-B100: E receptor pathway. Results suggest that less of the glycated LDL may enter the cells via scavenger receptors, and very minute amount via non-saturable receptor-independent pathways.
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Affiliation(s)
- A Gugliucci Creriche
- Biochemistry Laboratory, Faculté de Pharmacie, Université Louis Pasteur, Illkirch, France
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22
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Fisher WR, Zech LA, Kilgore LL, Stacpoole PW. Metabolic pathways of apolipoprotein B in heterozygous familial hypercholesterolemia: studies with a [3H]leucine tracer. J Lipid Res 1991. [DOI: 10.1016/s0022-2275(20)41637-2] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
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23
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Vega GL, Grundy SM. Does measurement of apolipoprotein B have a place in cholesterol management? ARTERIOSCLEROSIS (DALLAS, TEX.) 1990; 10:668-71. [PMID: 2206113 DOI: 10.1161/01.atv.10.5.668] [Citation(s) in RCA: 48] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Affiliation(s)
- G L Vega
- Department of Clinical Nutrition, University of Texas Southwestern Medical Center, Dallas
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24
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Chuck SL, Yao Z, Blackhart BD, McCarthy BJ, Lingappa VR. New variation on the translocation of proteins during early biogenesis of apolipoprotein B. Nature 1990; 346:382-5. [PMID: 2374610 DOI: 10.1038/346382a0] [Citation(s) in RCA: 88] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Apolipoprotein B (apo B) is crucial for the transport of cholesterol in humans. It is a large secretory protein that mediates the uptake of low-density lipoproteins and renders several forms of lipid droplets soluble in the blood. The binding of lipid by apo B also prevents this hydrophobic protein from precipitating in aqueous solution. In the endoplasmic reticulum, nascent secretory proteins must be translocated through an aqueous channel in the membrane into the aqueous lumen, so some novel form of processing may be necessary to maintain the solubility of apo B during its translocation. We have discovered that the biogenesis of apo B in cell-free systems does indeed involve a new variation on protein translocation: unlike typical secretory proteins, apo B is synthesized as a series of transmembrane chains with large cytoplasmic domains and progressively longer amino-terminal regions that are protected against added proteases during the translocation process. In contrast to typical transmembrane proteins, these transmembrane chains are not integrated into the bilayer. Moreover, the transmembrane chains with the shortest protected domains are precursors of forms whose protection is progressively extended to cover the length of the protein. This stepwise conversion occurs post-translationally for the most part. We propose a model on the basis of these findings for the biogenesis of apo B.
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Affiliation(s)
- S L Chuck
- Department of Medicine, University of California 94143
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25
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26
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Bigler RD, Brown HM, Guyre PM, Lund-Katz S, Scerbo L, Esfahani M. Effect of low-density lipoprotein on the expression of high affinity Fc gamma receptors. BIOCHIMICA ET BIOPHYSICA ACTA 1989; 1011:102-9. [PMID: 2523738 DOI: 10.1016/0167-4889(89)90195-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
A substrain of the human monocyte-like cell line U937, which is a cholesterol auxotroph, was used to study the effect of cellular cholesterol depletion on the expression of the type I Fc receptor for IgG (Fc gamma RI). Measurement of Fc gamma RI expression was performed by immunofluorescence and flow cytometry using the monoclonal antibody (mAb) 32.2, which is specific for an epitope on Fc gamma RI, and monomeric IgG2a, which binds to the ligand binding site of Fc gamma RI. Incubation of these cells for 24 h in growth medium containing delipidated fetal calf serum depletes cellular cholesterol without affecting growth or viability. While incubation of U937 cells with human interferon-gamma (IFN-gamma) increased Fc gamma RI expression, cholesterol depletion after cell growth in media containing delipidated serum and IFN-gamma resulted in reduced binding of both mAb 32.2 and IgG2a. A significant decrease in the number of cell surface binding sites, as measured by mean fluorescence intensity, was observed after cholesterol depletion. Supplementation of the delipidated serum medium with pure cholesterol in an ethanol/bovine serum albumin mixture, which replenished cellular cholesterol and supported growth, failed to restore antibody binding significantly. In contrast, low-density lipoprotein (LDL) which also delivered cholesterol to the cells restored binding both in terms of the number of the reactive cells and cell surface receptor density. High-density lipoprotein (HDL3), which does not deliver cholesterol to the cells, showed results similar to those obtained with pure cholesterol. This indicates that either LDL cholesterol is better utilized for membrane synthesis than pure cholesterol or that LDL provides another component, in addition to cholesterol, which is required for expression of Fc gamma RI, but not for growth. These studies indicate a role for LDL in regulating the expression of Fc gamma RI on the cell surface.
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Affiliation(s)
- R D Bigler
- Department of Neoplastic Diseases, Hahnemann University School of Medicine, Philadelphia, PA 19102
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27
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Puppione DL, Nicolosi RJ, Kowala MC, Schumaker VN. Low density lipoprotein heterogeneity in the cebus monkey. J Lipid Res 1989. [DOI: 10.1016/s0022-2275(20)38326-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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28
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Phillips ML, Schumaker VN. Conformation of apolipoprotein B after lipid extraction of low density lipoproteins attached to an electron microscope grid. J Lipid Res 1989. [DOI: 10.1016/s0022-2275(20)38356-5] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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29
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Elovson J, Chatterton JE, Bell GT, Schumaker VN, Reuben MA, Puppione DL, Reeve JR, Young NL. Plasma very low density lipoproteins contain a single molecule of apolipoprotein B. J Lipid Res 1988. [DOI: 10.1016/s0022-2275(20)38425-x] [Citation(s) in RCA: 99] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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