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Shieh YT, Chang CT, Toh JJ, Hsu YH, Chang IT, Hsia MH, Liu MY. Cyclodextrin-micellar electrokinetic chromatography of apolipoproteins on human very low-density lipoprotein. Electrophoresis 2020; 41:1333-1343. [PMID: 32390137 DOI: 10.1002/elps.202000065] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2019] [Revised: 04/19/2020] [Accepted: 05/04/2020] [Indexed: 11/05/2022]
Abstract
The apolipoproteins (APOs) of human very low-density lipoprotein (VLDL) were investigated by an optimized cyclodextrin-micellar electrokinetic chromatography (CD-MEKC) method. The separation buffer consisted of 20 mM sodium phosphate, 40 mM bile salts (50% sodium cholate and 50% sodium deoxycholate), 25 mM carboxymethyl-β-cyclodextrin (CM-β-CD) (pH 7.0). For CD-MEKC separation, a sample injection time of 12 s, a separation voltage of 15 KV, and a capillary temperature of 15°C were chosen. The optimal CD-MEKC method showed good resolution and repeatability for VLDL APOs. Identification and quantitation of VLDL APOs CI, CIII, and E were based on comparison with human APO standards. Good linear relationships with correlation coefficient (R2 ) 0.99 were obtained for APOs CI, CIII, and E standards. For these three APOs, the linear ranges were within 0.01-0.54 mg/mL, and the concentration limits of detection (LODs) were lower than 0.02 mg/mL. Moreover, VLDL APOs from four uremic patients and four healthy subjects were compared. The uremic and healthy CD-MEKC profiles showed dramatic difference. The levels of APO CIII were significantly higher for two patients, and the level of APO E was significantly higher for one patient. This study might be helpful for following the disease development of uremia and cardiovascular disease (CVD) in the future.
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Affiliation(s)
- Ying-Tzu Shieh
- Department of Chemistry, National Changhua University of Education, Changhua, Taiwan
| | - Chiz-Tzung Chang
- China Medical University Hospital, Taichung, Taiwan.,Department of Internal Medicine, College of Medicine, China Medical University, Taichung, Taiwan
| | - Jia-Jia Toh
- Department of Chemistry, National Changhua University of Education, Changhua, Taiwan
| | - Yun-Hsun Hsu
- Department of Chemistry, National Changhua University of Education, Changhua, Taiwan
| | - I-Ting Chang
- Department of Chemistry, National Changhua University of Education, Changhua, Taiwan
| | - Min-Hui Hsia
- Department of Chemistry, National Changhua University of Education, Changhua, Taiwan
| | - Mine-Yine Liu
- Department of Chemistry, National Changhua University of Education, Changhua, Taiwan
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2
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Hsu YH, Toh JJ, Chang CT, Liu MY. Investigating apolipoproteins of human high-density lipoprotein by cyclodextrin-micellar electrokinetic chromatography. J Chromatogr A 2019; 1593:164-173. [PMID: 30738616 DOI: 10.1016/j.chroma.2019.01.073] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2018] [Revised: 01/22/2019] [Accepted: 01/25/2019] [Indexed: 12/01/2022]
Abstract
A cyclodextrin-micellar electrokinetic chromatography (CD-MEKC) method has been developed to determine the apolipoproteins (apos) of human high-density lipoprotein (HDL). The optimal CD-MEKC conditions included a separation buffer mixture of 5 mM sodium phosphate, 40 mM bile salts (50% sodium cholate and 50% sodium deoxycholate), 25 mM carboxymethyl-β-CD (CM-β-CD) and pH 7.0. The separation voltage was 15 kV, and the capillary temperature was 15℃. The CD-MEKC profiles of human HDL apolipoproteins showed good repeatability and sensitivity. Linear analysis has been performed for human apolipoprotein standards including apos AI, AII, CI, CII, CIII and E. Linear regression lines with coefficients of determination (R2) greater than 0.99 were obtained for apos AI, AII, CI, CII and E. The linear ranges for the six apolipoproteins were within 0.18-0.70 mg/mL, and the concentration limits of detection (LOD) were lower than 0.0617 mg/mL. Apos AI, AII, CI and CIII were identified and quantified in human HDL by comparing with apolipoprotein standards. Furthermore, the CD-MEKC profiles of uremic patients differed significantly from healthy subjects. The concentration ratios of apo AI/apo CIII were significantly lower for uremic patients than healthy subjects. This study demonstrated the feasibility of determining human HDL apolipoproteins by CD-MEKC. In the future, it might help monitor the progression of uremia and cardiovascular disease.
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Affiliation(s)
- Yun-Hsun Hsu
- Department of Chemistry, National Changhua University of Education, Changhua, Taiwan
| | - Jia-Jia Toh
- Department of Chemistry, National Changhua University of Education, Changhua, Taiwan
| | | | - Mine-Yine Liu
- Department of Chemistry, National Changhua University of Education, Changhua, Taiwan.
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3
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Mischak H, Vlahou A, Ioannidis JP. Technical aspects and inter-laboratory variability in native peptide profiling: The CE–MS experience. Clin Biochem 2013; 46:432-43. [DOI: 10.1016/j.clinbiochem.2012.09.025] [Citation(s) in RCA: 150] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2012] [Revised: 09/18/2012] [Accepted: 09/27/2012] [Indexed: 02/08/2023]
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4
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Liu YN, Shu TY, Xie HG, Lai WT, Liao YH, Su MY, Lin YS, Chen YY, Lin YJ, Chong CP, Liu MY. Characterization of in vitro modified human very low-density lipoprotein particles and phospholipids by capillary electrophoresis. Int J Mol Sci 2012. [PMID: 23208377 PMCID: PMC3546697 DOI: 10.3390/ijms131216400] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A simple capillary zone electrophoresis (CZE) method was used to characterize human very low-density lipoprotein (VLDL) particles for four healthy donors. One major peak was observed for native, in vitro oxidized and glycated VLDL particles. The effective mobilities and peak areas of the capillary electrophoresis (CE) profiles showed good reproducibility and precision. The mobility of the oxidized VLDL peak was higher than that of the native VLDL. The mobility of the glycated VLDL peak was similar to that of the native VLDL. Phospholipids isolated from VLDL particles were analyzed by our recently developed micellar electrokinetic chromatography (MEKC) with a high-salt stacking method. At absorbance 200 nm, the native VLDL phospholipids showed a major peak and a minor peak for each donor. For oxidized VLDL phospholipids, the area of the major peak reduced for three donors, possibly due to phospholipid decomposition. For glycated VLDL phospholipids, the peak mobilities were more positive than native VLDL phospholipids for two donors, possibly due to phospholipid-linked advanced glycation end products (AGEs). Very interestingly, at absorbance 234 nm, the major peak of oxidized VLDL phospholipids was resolved as two peaks for each donor, possibly due to conjugated dienes formed upon oxidation.
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Affiliation(s)
- Yi-Ning Liu
- Department of Chemistry, National Changhua University of Education, Changhua 50058, Taiwan.
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Larner CD, Henriquez RR, Johnson JD, Macfarlane RD. Developing high performance lipoprotein density profiling for use in clinical studies relating to cardiovascular disease. Anal Chem 2011; 83:8524-30. [PMID: 21970640 PMCID: PMC3220625 DOI: 10.1021/ac2018124] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022]
Abstract
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Early detection of the beginning stage of cardiovascular disease
(CVD) is an approach to prevention because the process is reversible
at this stage. Consequently, several methods for screening for CVD
have been introduced in recent years incorporating different analytical
methods for characterizing the population of blood-borne lipoprotein
subclasses. The gold standard method for lipoprotein subclassification
is based on lipoprotein density measured by sedimentation equilibrium
using the ultracentrifuge. However, this method has not been adopted
for clinical studies because of difficulties in achieving the precision
required for distinguishing individuals with and without CVD particularly
when statistical classification methods are used. The objective of
this study was to identify and improve the major factors that influence
the precision of measurement of lipoprotein density profile by sedimentation
equilibrium analysis and labeling with a fluorescent probe. The study
has two phases, each contributing to precision. The first phase focuses
on the ultracentrifugation-related variables, and the second phase
addresses those factors involved in converting the fluorescent lipoprotein
density profile to a digital format compatible with statistical analysis.
The overall improvement in precision was on the order of a factor
of 5, sufficient to be effectively applied to ongoing classification
studies relating to CVD risk assessment.
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Affiliation(s)
- Craig D Larner
- Department of Chemistry, Texas A&M University, 3255 TAMU, College Station, Texas 77843-3255, United States
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6
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Tabuchi M, Seo M, Inoue T, Ikeda T, Kogure A, Inoue I, Katayama S, Matsunaga T, Hara A, Komoda T. Geometrical Separation Method for Lipoproteins Using Bioformulated-Fiber Matrix Electrophoresis: Size of High-Density Lipoprotein Does Not Reflect Its Density. Anal Chem 2010; 83:1131-6. [DOI: 10.1021/ac102402c] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Mari Tabuchi
- Department of Chemistry, Faculty of Science, Rikkyo University, 3-34-1, Nishi-Ikebukuro, Toshima-ku, Tokyo, 171-8501, Japan
- Research Information Center for Extremophile, Rikkyo University, 3-34-1, Nishi-Ikebukuro, Toshima-ku, Tokyo, 171-8501, Japan
| | - Makoto Seo
- Department of Biochemistry, Faculty of Medicine, Saitama Medical University, 38 Morohongo, Moroyama, Iruma-gun, Saitama 350-0495, Japan
| | - Takayuki Inoue
- Department of Chemistry, Faculty of Science, Rikkyo University, 3-34-1, Nishi-Ikebukuro, Toshima-ku, Tokyo, 171-8501, Japan
| | - Takeshi Ikeda
- Department of Chemistry, Faculty of Science, Rikkyo University, 3-34-1, Nishi-Ikebukuro, Toshima-ku, Tokyo, 171-8501, Japan
| | - Akinori Kogure
- Surface Analysis Division, Shimadzu Analytical & Measuring Center, Inc. 380-1, Horiyamashita, Hadano-city, Kanagawa, 259-1304, Japan
| | - Ikuo Inoue
- Department of Endocrinology and Diabetes, Faculty of Medicine, Saitama Medical University, 38 Morohongo, Moroyama, Iruma-gun, Saitama 350-0495, Japan
| | - Shigehiro Katayama
- Department of Endocrinology and Diabetes, Faculty of Medicine, Saitama Medical University, 38 Morohongo, Moroyama, Iruma-gun, Saitama 350-0495, Japan
| | - Toshiyuki Matsunaga
- Laboratory of Biochemistry, Gifu Pharmaceutical University, 5-6-1 Mitahora-higashi, Gifu 502-8585, Japan
| | - Akira Hara
- Laboratory of Biochemistry, Gifu Pharmaceutical University, 5-6-1 Mitahora-higashi, Gifu 502-8585, Japan
| | - Tsugikazu Komoda
- Department of Biochemistry, Faculty of Medicine, Saitama Medical University, 38 Morohongo, Moroyama, Iruma-gun, Saitama 350-0495, Japan
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7
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Ikeda T, Seo M, Inoue I, Katayama S, Matsunaga T, Hara A, Komoda T, Tabuchi M. Direct and simple fluorescence detection method for oxidized lipoproteins. Anal Chem 2010; 82:1128-32. [PMID: 20043691 DOI: 10.1021/ac902018a] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The quantification of low-density lipoprotein (LDL) and high-density lipoprotein (HDL) is currently one of the most important clinical measurements for characterizing metabolic syndrome. However, recent studies have revealed additional factors that may be more strongly associated with the coronary heart disease than simple measurement of LDL or HDL levels, such as small dense (sd) LDL particles and oxidized LDL or HDL particles. Although several methods using enzyme-antibody detection systems or fluorescent probes have been devised to characterize these factors, such methods are expensive to implement for clinical measurements. Here, we present a straightforward analytical method for direct quantitation of oxidized lipoproteins by fluorescence spectrometry, with excitation in the UV (365 +/- 10 nm) or visible (470 +/- 10 nm) range and emission detected at 450 +/- 30 nm or 535 +/- 15 nm. This method can be readily applied for clinical measurement in patients with dyslipidemia using only 1 microL of 1 mg/mL of lipoprotein and without the need for any expensive detection antibodies. Using this new technique, biological samples from patients with dyslipidemia showed higher fluorescence intensities than samples from normal subjects when detecting oxidized LDL and light HDL (d = 1.063-1.125 g/mL), whereas samples from patients with dyslipidemia showed lower fluorescence intensities than samples from normal subjects when measuring oxidized heavy HDL (d = 1.125-1.210 g/mL) levels.
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Affiliation(s)
- Takeshi Ikeda
- Department of Chemistry, Graduate School of Science, Rikkyo University, 3-34-1, Nishi-Ikebukuro, Toshima-ku, Tokyo, 171-8501, Japan
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8
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Characterization of in vitro modified human high-density lipoprotein particles and phospholipids by capillary zone electrophoresis and LC ESI-MS. J Chromatogr B Analyt Technol Biomed Life Sci 2009; 877:3495-505. [DOI: 10.1016/j.jchromb.2009.08.022] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2009] [Revised: 08/07/2009] [Accepted: 08/12/2009] [Indexed: 11/22/2022]
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9
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Wang H, Wang HM, Jin QH, Cong H, Zhuang GS, Zhao JL, Sun CL, Song HW, Wang W. Microchip-based small, dense low-density lipoproteins assay for coronary heart disease risk assessment. Electrophoresis 2008; 29:1932-41. [DOI: 10.1002/elps.200700631] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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10
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Shimazaki Y, Miyamoto M. Analysis of lipid hydrolytic activity by esterase on blotting membrane followed by separation using non-denaturing two-dimensional gel electrophoresis. Biotechnol Bioeng 2007; 98:732-6. [PMID: 17385750 DOI: 10.1002/bit.21437] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
After separation by microscale non-denaturing two-dimensional gel electrophoresis (2DE) and transferring to a blotting membrane, major proteins are detected by a staining of direct blue 71 in a neutral solution. The carboxylesterase on the membrane hydrolyzes phosphatidylcholine after the spot of carboxylesterase is excised from the membrane, and incubated with phosphatidylcholine. Lipids of human serum proteins and the purified human high density lipoprotein (HDL) are removed by enzymatic hydrolysis when human serum proteins and the purified HDL are respectively incubated with the spot of carboxylesterase on the membrane. These results indicate that carboxylesterase on the membrane hydrolyzes not only lipids such as phosphatidylcholine but also lipids of lipoproteins such as HDL after separation by the 2DE, transferring to the membrane and staining without impairing the activity. These results also indicate that a micro-immobilized enzyme reactor on the membrane can be produced when biological enzymes are separated by microscale 2DE, transferred to the membrane and stained without impairing their activities.
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Affiliation(s)
- Youji Shimazaki
- Graduate School of Science and Engineering (Science Section), Venture Business Laboratory, Ehime University, Matsuyama City 790-8577, Japan.
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11
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Shihabi ZK. REVIEW OF APPLICATIONS OF CAPILLARY ELECTROPHORESIS FOR CLINICAL ANALYSIS. J LIQ CHROMATOGR R T 2006. [DOI: 10.1081/jlc-100101437] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Affiliation(s)
- Zak K. Shihabi
- a Pathology Department , Wake Forest University Baptist Medical Center , Winston-Salem, NC, 27157, U.S.A
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12
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Langlois MR, Blaton VH. Historical milestones in measurement of HDL-cholesterol: Impact on clinical and laboratory practice. Clin Chim Acta 2006; 369:168-78. [PMID: 16579980 DOI: 10.1016/j.cca.2006.01.031] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2005] [Accepted: 01/31/2006] [Indexed: 11/16/2022]
Abstract
High-density lipoprotein cholesterol (HDL-C) comprises a family of particles with differing physicochemical characteristics. Continuing progress in improving HDL-C analysis has originated from two separate fields-one clinical, reflecting increased attention to HDL-C in estimating risk for coronary heart disease (CHD), and the other analytical, reflecting increased emphasis on finding more reliable and cost-effective HDL-C assays. Epidemiologic and prospective studies established the inverse association of HDL-C with CHD risk, a relationship that is consistent with protective mechanisms demonstrated in basic research and animal studies. Atheroprotective and less atheroprotective HDL subpopulations have been described. Guidelines on primary and secondary CHD prevention, which increased the workload in clinical laboratories, have led to a revolution in HDL-C assay technology. Many analytical techniques including ultracentrifugation, electrophoresis, chromatography, and polyanion precipitation methods have been developed to separate and quantify HDL-C and HDL subclasses. More recently developed homogeneous assays enable direct measurement of HDL-C on an automated analyzer, without the need for manual pretreatment to separate non-HDL. Although homogeneous assays show improved accuracy and precision in normal serum, discrepant results exist in samples with atypical lipoprotein characteristics. Hypertriglyceridemia and monoclonal paraproteins are important interfering factors. A novel approach is nuclear magnetic resonance spectroscopy that allows rapid and reliable analysis of lipoprotein subclasses, which may improve the identification of individuals at increased CHD risk. Apolipoprotein A-I, the major protein of HDL, has been proposed as an alternative cardioprotective marker avoiding the analytical limitations of HDL-C.
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Affiliation(s)
- Michel R Langlois
- Department of Clinical Chemistry, AZ St. Jan Hospital, Ruddershove 10, B-8000 Brugge, Belgium.
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13
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Ping G, Zhu B, Jabasini M, Xu F, Oka H, Sugihara H, Baba Y. Analysis of Lipoproteins by Microchip Electrophoresis with High Speed and High Reproducibility. Anal Chem 2005; 77:7282-7. [PMID: 16285676 DOI: 10.1021/ac050896w] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A method for the fast analysis of lipoproteins by microchip electrophoresis with light-emitting diode confocal fluorescence detection has been developed. Lipoproteins labeled with BODIPY FL C(5)-ceramide are found to strongly adsorb on the bare surface of a poly(methyl methacrylate) (PMMA) microchip. Sodium dodecyl sulfate and cetyltrimethylammonium bromide were therefore utilized to alter lipoproteins and channel surface to make them bear the same type of charge. After modification, the peak shape of lipoproteins was greatly improved, demonstrating lipoprotein adsorption on a PMMA chip dramatically reduced due to electrostatic repulsion. In addition, polymers were added into the running buffer to suppress electroosmotic flow and to serve as a sieving matrix. As a result, lipoprotein separation was manipulated by both electrophoretic mobilities and particle sizes. Various separation parameters including surfactant concentration, buffer pH, and polymer concentration as well as on-line concentration were investigated systematically. Under optimal conditions, two baseline separations of standard lipoproteins including high-density lipoprotein, low-density lipoprotein, and very low-density lipoprotein were achieved with different selectivity. This method affords high separation speed (within 100 s) and high reproducibility. The intraassay and interassay RSDs of lipoprotein migration times were in the range of 0.90-1.9%, indicating this method is highly reliable.
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Affiliation(s)
- Guichen Ping
- Nanotechnology Laboratory, Advanced Technology Research Laboratories, Matsushita Electric Industrial Co. Ltd., Seika, Soraku, Kyoto, Japan.
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14
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Yamaguchi Y, Kunitomo M, Haginaka J. Assay methods of modified lipoproteins in plasma. J Chromatogr B Analyt Technol Biomed Life Sci 2002; 781:313-30. [PMID: 12450666 DOI: 10.1016/s1570-0232(02)00433-6] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Modified lipoproteins, especially oxidatively modified low-density lipoprotein (Ox-LDL), are present in the plasma of patients with atherosclerosis and related diseases. The modification of LDL is believed to play an important role in the development of atherosclerosis. Thus, measurement of plasma Ox-LDL is essential not only for investigating its relevance to atherosclerotic diseases, but also for diagnosis. Chromatographic methods are effective for indirectly measuring the oxidatively modified state of LDL or directly measuring the modified LDL. Indirect determination can be done by estimating the LDL subfraction, LDL particle size, oxidized amino acids in apolipoprotein B, lipid hydroperoxide or F(2)-isoprostane in LDL. Direct determination of the modified LDL in plasma can be done with chromatographic methods such as anion-exchange chromatography and size-exclusion chromatography. Other methods for estimating the modified state of LDL include electromigration methods such as agarose gel, polyacrylamide gradient gel and capillary electrophoresis. Recently, enzyme-linked immunosorbent assay methods of malondialdehyde (MDA)-LDL and autoantibodies against Ox-LDL have been developed to assess Ox-LDL in plasma. This review article summarizes the detection and assay methods of modified lipoproteins in plasma.
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Affiliation(s)
- Yu Yamaguchi
- Department of Pharmacology, Faculty of Pharmaceutical Sciences, Mukogawa Women's University, 11-68, Koshien Kyuban-cho, Nishinomiya 663-8179, Japan.
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15
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Weiller BH, Ceriotti L, Shibata T, Rein D, Roberts MA, Lichtenberg J, German JB, de Rooij NF, Verpoorte E. Analysis of lipoproteins by capillary zone electrophoresis in microfluidic devices: assay development and surface roughness measurements. Anal Chem 2002; 74:1702-11. [PMID: 12033263 DOI: 10.1021/ac011096y] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The development of a new assay for lipoproteins by capillary electrophoresis in fused-silica capillaries and in glass microdevices is described in this paper. The separation of low-density (LDL) and high-density (HDL) lipoproteins by capillary zone electrophoresis is demonstrated in fused-silica capillaries with both UV absorption and laser-induced fluorescence detection. This separation was accomplished using Tricine buffer (pH 9.0) with methylglucamine added as a dynamic coating. With UV detection, LDL eluted as a relatively sharp peak with a migration time of approximately 11 min and HDL eluted as a broad peak with a migration time of 12.5 min. Fluorescence detection of lipoproteins stained with NBD-ceramide was used with the same buffer system to give comparable results. Furthermore, fluorescence staining of human serum samples yielded results similar to the fluorescently stained LDL and HDL fractions, showing that this method can be used to quantify lipoproteins in serum samples. The method was also used to detect lipoproteins in glass micro-CE devices. Very similar results were obtained in microdevices although with much faster analysis times, LDL eluted as a sharp peak at approximately 25 s and HDL as a broad peak at slightly longer time. In addition, higher resolution was obtained on chips. To our knowledge, these results show the first separation and detection of lipoproteins in a microfluidic device using native serum samples. Atomic force microscopy was used to characterize the rms surface roughness (Rq) of microfluidic channels directly. Devices with different surface roughness values were fabricated using two different etchants for Pyrex wafers with a polysilicon masking layer. Using 49% HF, the measured roughness is Rq = 10.9 +/- 1.6 nm and with buffered HF (NH4F + HF) the roughness is Rq = 2.4 +/- 0.7 nm. At this level of surface roughness, there is no observable effect on the performance of the devices for this lipoprotein separation.
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Affiliation(s)
- Bruce H Weiller
- Institute of Microtechnology, University of Neuchâtel, Switzerland
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16
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Abstract
One of the weak points of capillary electrophoresis is the need to implement rigorously sample pretreatment because its great impact on the quality of the qualitative and quantitative results provided. One of the approaches to solve this problem is through the symbiosis of automatic continuous flow systems (CFSs) and capillary electrophoresis (CE). In this review a systematic approach to CFS-CE coupling is presented and discussed. The design of the corresponding interface depends on three factors, namely: (a) the characteristics of the CFS involved which can be non-chromatographic and chromatographic; (b) the type of CE equipment: laboratory-made or commercially available; and (c) the type of connection which can be in-line (on-capillary), on-line or mixed off/on-line. These are the basic criteria to qualify the hyphenation of CFS (solid-phase extraction, dialysis, gas diffusion, evaporation, direct leaching) with CE described so far and applied to determine a variety of analytes in many different types of samples. A critical discussion allows one to demonstrate that this symbiosis is an important topic in research and development, besides separation and detection, to consolidate CE as a routine analytical tool.
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Affiliation(s)
- M Valcárcel
- Analytical Chemistry Division, University of Córdoba, Spain.
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17
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Characterization and quantification of serum lipoprotein subfractions by capillary isotachophoresis: relationships with lipid, apolipoprotein, and lipoprotein levels. J Lipid Res 1999. [DOI: 10.1016/s0022-2275(20)32436-6] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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18
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Abstract
This review article with 125 references describes recent developments in capillary zone electrophoresis of proteins. It encompasses approximately the last two years, from the previous review (V. Dolník, Electrophoresis 1997, 18, 2353-2361) through Spring 1999. Topics covered include modeling of the electrophoretic properties of proteins, sample preconcentration and derivatization, wall coatings, improving selectivity, special detection techniques, and applications.
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Affiliation(s)
- V Dolník
- Molecular Dynamics, Sunnyvale, CA 94086, USA.
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19
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Thormann W, Wey AB, Lurie IS, Gerber H, Byland C, Malik N, Hochmeister M, Gehrig C. Capillary electrophoresis in clinical and forensic analysis: recent advances and breakthrough to routine applications. Electrophoresis 1999; 20:3203-36. [PMID: 10596826 DOI: 10.1002/(sici)1522-2683(19991001)20:15/16<3203::aid-elps3203>3.0.co;2-e] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
This paper is a comprehensive review article on capillary electrophoresis (CE) in clinical and forensic analysis. It is based upon the literature of 1997 and 1998, presents CE examples in major fields of application, and provides an overview of the key achievements encountered, including those associated with the analysis of drugs, serum proteins, hemoglobin variants, and nucleic acids. For CE in clinical and forensic analysis, the past two years witnessed a breakthrough to routine applications. As most coauthors of this review are associated with diagnostic or forensic laboratories now using CE on a routine basis, this review also contains data from routine applications in drug, protein, and DNA analysis. With the first-hand experience of providing analytical service under stringent quality control conditions, aspects of quality assurance, assay specifications for clinical and forensic CE and the pros and cons of this maturing, cost-and pollution-controlled age technology are also discussed.
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Affiliation(s)
- W Thormann
- Department of Clinical Pharmacology, University of Bern, Switzerland.
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20
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Abstract
Analyses of proteins in complex mixtures such as cell lyzates are presently performed mainly by sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis. For structural analysis, each protein in a spot is digested with proteases and the fragment peptides are subjected to Edman sequencing and/or mass spectrometry. These works aim at the total analysis of proteins in a complex mixture and reconstruction of their cooperative functions. Genomic studies are now being combined with these proteomic studies. This review article focuses on the application of capillary electrophoresis aiming at the total analysis of complex protein systems or structural analysis of each separated protein. From this viewpoint, articles on capillary zone electrophoresis, capillary isoelectric focusing, and sieving SDS capillary electrophoresis are reviewed. Since these techniques of capillary electrophoresis have been thoroughly reviewed previously, papers published in 1997 and 1998 are mainly covered.
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Affiliation(s)
- T Manabe
- Department of Chemistry, Faculty of Science, Ehime University, Matsuyama-City, Japan.
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Abstract
Capillary electrophoresis provides a valuable analytical tool for the analysis of apolipoproteins and lipoproteins. Sodium dodecyl sulfate (SDS) capillary gel electrophoresis can resolve human and animal apolipoprotein (apo) A-I, apo A-II, apo E and apo A-IV in isolated high density lipoproteins (HDLs) and is capable of analysing HDL apo A-I and apo A-II content with a coefficient of variation (CV) of less than 5%. Capillary zone electrophoresis (CZE) using coated capillaries with Tricine-urea buffer can also be used for the analysis of HDL apolipoproteins and is also capable of resolving apo A-I isoforms, pro-apo A-I, mature apo A-I and deamidated apo A-I. Furthermore it can separate human A-I from endogenous rabbit A-I in transgenic rabbits expressing the human apo A-I gene. Capillary isoelectric focusing can also separate apo A-I isoforms. Analysis of charge-modified low density lipoprotein (LDL) (ox-LDL) produced by in vitro lipid peroxidation can be performed by CZE and the technique can be used to monitor simultaneous changes in the electrophoretic mobility and absorption spectra of LDL.
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Affiliation(s)
- J Stocks
- Department of Cardiovascular Biochemistry, St Bartholomew's and the Royal London College of Medicine and Dentistry, UK.
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Affiliation(s)
- Yan Xu
- Department of Chemistry, Cleveland State University, Cleveland, Ohio 44115
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23
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Affiliation(s)
- D Perrett
- Department of Medicine, St Bartholomew's, London, UK
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