The Experts below are selected from a list of 9711 Experts worldwide ranked by ideXlab platform

Xavier Bossuyt - One of the best experts on this subject based on the ideXlab platform.

  • interferences in clinical capillary Zone Electrophoresis of serum proteins
    2004
    Co-Authors: Xavier Bossuyt
    Abstract:

    Capillary Zone Electrophoresis (CZE) of serum proteins has become a well-accepted method for the separation of serum proteins and for the detection of monoclonal proteins in clinical laboratories. As CZE uses ultraviolet detection for direct protein quantification, exogenous ultraviolet-absorbing substances are a novel challenge, not present in conventional gel-based methods in which protein is quantified by dye binding. This minireview gives a survey of interfering substances, including iodinated contrast agents and antibiotics.

  • separation of serum proteins by automated capillary Zone Electrophoresis
    2003
    Co-Authors: Xavier Bossuyt
    Abstract:

    Capillary Zone Electrophoresis (CZE) of serum proteins is increasingly gaining impact in clinical laboratories. Two automated multichannel instruments dedicated to the separation of serum proteins have become available over the last 6 years, the Paragon CZE 2000 (Beckman Coulter, CA, USA) and, more recently, the Capillarys (Sebia, France). This review focuses on the performance of these commercial instruments to separate serum proteins in a clinical laboratory setting. The utility of CZE to recognize various dysproteinemias and to detect and identify monoclonal proteins will be described and systematically reviewed. The reader will be provided with a summation and an understanding of CZE-specific interference.

  • interference of radio opaque agents in clinical capillary Zone Electrophoresis
    1999
    Co-Authors: Xavier Bossuyt, Alex Mewis, Norbert Blanckaert
    Abstract:

    Capillary Zone Electrophoresis (CZE) has emerged as a novel technique for the rapid and effective separation of serum proteins (1)(2)(3)(4)(5)(6)(7)(8). Recently, a multichannel automated system for CZE of human serum proteins (Paragon 2000 clinical capillary Electrophoresis system; Beckman Instruments) became commercially available; this system offers a clinically reliable alternative to cellulose acetate and agarose Electrophoresis. CZE has the advantage of automation, improved precision, and a faster turnaround time (6)(8). In the conventional methods, quantification of the protein fractions is based on dye binding, whereas CZE uses ultraviolet detection at 214 nm for direct protein quantification via the peptide bonds. We asked whether intravascular agents such as radio-contrast media that absorb at 214 nm would simulate a monoclonal component on CZE. We performed high resolution agarose Electrophoresis with the Hydrasys analyzer (Sebia), using Hydragel 15 HR gels (Sebia) according to the …

Jongyoon Han - One of the best experts on this subject based on the ideXlab platform.

  • tunable membranes for free flow Zone Electrophoresis in pdms microchip using guided self assembly of silica microbeads
    2013
    Co-Authors: Yong Ak Song, Steven R Tannenbaum, John S Wishnok, Jongyoon Han
    Abstract:

    In this paper, we evaluate the strategy of using self-assembled microbeads to build a robust and tunable membrane for free-flow Zone Electrophoresis in a PDMS microfluidic chip. To fabricate a porous membrane as a salt bridge for free-flow Zone Electrophoresis, we used silica or polystyrene microbeads between 3–6 μm in diameter and packed them inside a microchannel. After complete evaporation, we infiltrated the porous microbead structure with a positively or negatively charged hydrogel to modify its surface charge polarity. Using this device, we demonstrated binary sorting (separation of positive and negative species at a given pH) of peptides and dyes in standard buffer systems without using sheath flows. The sample loss during sorting could be minimized by using ion selectivity of hydrogel-infiltrated microbead membranes. Our fabrication method enables building a robust membrane for pressure-driven free-flow Zone Electrophoresis with tunable pore size as well as surface charge polarity.

  • free flow Zone Electrophoresis of peptides and proteins in pdms microchip for narrow pi range sample prefractionation coupled with mass spectrometry
    2010
    Co-Authors: Yong Ak Song, Steven R Tannenbaum, John S Wishnok, Michael Chan, Christopher Celio, Jongyoon Han
    Abstract:

    In this paper, we are evaluating the strategy of sorting peptides/proteins based on the charge to mass without resorting to ampholytes and/or isoelectric focusing, using a single- and two-step free-flow Zone Electrophoresis. We developed a simple fabrication method to create a salt bridge for free-flow Zone Electrophoresis in PDMS chips by surface printing a hydrophobic layer on a glass substrate. Since the surface-printed hydrophobic layer prevents plasma bonding between the PDMS chip and the substrate, an electrical junction gap can be created for free-flow Zone Electrophoresis. With this device, we demonstrated a separation of positive and negative peptides and proteins at a given pH in standard buffer systems and validated the sorting result with LC/MS. Furthermore, we coupled two sorting steps via off-chip titration and isolated peptides within specific pI ranges from sample mixtures, where the pI range was simply set by the pH values of the buffer solutions. This free-flow Zone Electrophoresis sorti...

Steven R Tannenbaum - One of the best experts on this subject based on the ideXlab platform.

  • tunable membranes for free flow Zone Electrophoresis in pdms microchip using guided self assembly of silica microbeads
    2013
    Co-Authors: Yong Ak Song, Steven R Tannenbaum, John S Wishnok, Jongyoon Han
    Abstract:

    In this paper, we evaluate the strategy of using self-assembled microbeads to build a robust and tunable membrane for free-flow Zone Electrophoresis in a PDMS microfluidic chip. To fabricate a porous membrane as a salt bridge for free-flow Zone Electrophoresis, we used silica or polystyrene microbeads between 3–6 μm in diameter and packed them inside a microchannel. After complete evaporation, we infiltrated the porous microbead structure with a positively or negatively charged hydrogel to modify its surface charge polarity. Using this device, we demonstrated binary sorting (separation of positive and negative species at a given pH) of peptides and dyes in standard buffer systems without using sheath flows. The sample loss during sorting could be minimized by using ion selectivity of hydrogel-infiltrated microbead membranes. Our fabrication method enables building a robust membrane for pressure-driven free-flow Zone Electrophoresis with tunable pore size as well as surface charge polarity.

  • free flow Zone Electrophoresis of peptides and proteins in pdms microchip for narrow pi range sample prefractionation coupled with mass spectrometry
    2010
    Co-Authors: Yong Ak Song, Steven R Tannenbaum, John S Wishnok, Michael Chan, Christopher Celio, Jongyoon Han
    Abstract:

    In this paper, we are evaluating the strategy of sorting peptides/proteins based on the charge to mass without resorting to ampholytes and/or isoelectric focusing, using a single- and two-step free-flow Zone Electrophoresis. We developed a simple fabrication method to create a salt bridge for free-flow Zone Electrophoresis in PDMS chips by surface printing a hydrophobic layer on a glass substrate. Since the surface-printed hydrophobic layer prevents plasma bonding between the PDMS chip and the substrate, an electrical junction gap can be created for free-flow Zone Electrophoresis. With this device, we demonstrated a separation of positive and negative peptides and proteins at a given pH in standard buffer systems and validated the sorting result with LC/MS. Furthermore, we coupled two sorting steps via off-chip titration and isolated peptides within specific pI ranges from sample mixtures, where the pI range was simply set by the pH values of the buffer solutions. This free-flow Zone Electrophoresis sorti...

Yong Ak Song - One of the best experts on this subject based on the ideXlab platform.

  • tunable membranes for free flow Zone Electrophoresis in pdms microchip using guided self assembly of silica microbeads
    2013
    Co-Authors: Yong Ak Song, Steven R Tannenbaum, John S Wishnok, Jongyoon Han
    Abstract:

    In this paper, we evaluate the strategy of using self-assembled microbeads to build a robust and tunable membrane for free-flow Zone Electrophoresis in a PDMS microfluidic chip. To fabricate a porous membrane as a salt bridge for free-flow Zone Electrophoresis, we used silica or polystyrene microbeads between 3–6 μm in diameter and packed them inside a microchannel. After complete evaporation, we infiltrated the porous microbead structure with a positively or negatively charged hydrogel to modify its surface charge polarity. Using this device, we demonstrated binary sorting (separation of positive and negative species at a given pH) of peptides and dyes in standard buffer systems without using sheath flows. The sample loss during sorting could be minimized by using ion selectivity of hydrogel-infiltrated microbead membranes. Our fabrication method enables building a robust membrane for pressure-driven free-flow Zone Electrophoresis with tunable pore size as well as surface charge polarity.

  • free flow Zone Electrophoresis of peptides and proteins in pdms microchip for narrow pi range sample prefractionation coupled with mass spectrometry
    2010
    Co-Authors: Yong Ak Song, Steven R Tannenbaum, John S Wishnok, Michael Chan, Christopher Celio, Jongyoon Han
    Abstract:

    In this paper, we are evaluating the strategy of sorting peptides/proteins based on the charge to mass without resorting to ampholytes and/or isoelectric focusing, using a single- and two-step free-flow Zone Electrophoresis. We developed a simple fabrication method to create a salt bridge for free-flow Zone Electrophoresis in PDMS chips by surface printing a hydrophobic layer on a glass substrate. Since the surface-printed hydrophobic layer prevents plasma bonding between the PDMS chip and the substrate, an electrical junction gap can be created for free-flow Zone Electrophoresis. With this device, we demonstrated a separation of positive and negative peptides and proteins at a given pH in standard buffer systems and validated the sorting result with LC/MS. Furthermore, we coupled two sorting steps via off-chip titration and isolated peptides within specific pI ranges from sample mixtures, where the pI range was simply set by the pH values of the buffer solutions. This free-flow Zone Electrophoresis sorti...

Thormann Wolfgang - One of the best experts on this subject based on the ideXlab platform.

  • High-resolution capillary Zone Electrophoresis and mass spectrometry for distinction of undersialylated and hypoglycosylated transferrin glycoforms in body fluids.
    2020
    Co-Authors: Caslavsky Jitka, Schild Christof, Thormann Wolfgang
    Abstract:

    High-resolution capillary Zone Electrophoresis is used to distinguish transferrin glycoforms present in human serum, cerebrospinal fluid, and serum treated with neuraminidase and N-glycosidase F. The obtained data are compared to mass spectrometry data from the literature. The main focus is on the analysis of the various asialo-transferrin, monosialo-transferrin, and disialo-transferrin molecules found in these samples. The features of capillary Zone Electrophoresis and mass spectrometry are reviewed and highlighted in the context of the analysis of undersialylated and hypoglycosylated transferrin molecules. High-resolution capillary Zone Electrophoresis represents an effective tool to assess the diversity of transferrin patterns whereas mass spectrometry is the method of choice to elucidate structural identification about the glycoforms. Hypoglycosylated transferrin glycoforms present in sera of alcohol abusers and normal subjects are structurally identical to those in sera of patients with a congenital disorder of glycosylation type I. Asialo-transferrin, monosialo-transferrin and disialo-transferrin observed in sera of patients with a type II congenital disorder of glycosylation or a hemolytic uremic syndrome, in cerebrospinal fluid and after treatment of serum with neuraminidase are undersialylated transferrin glycoforms with two N-glycans of varying structure. Undersialylated disialo-transferrin is also observed in sera with high levels of trisialo-transferrin

  • High-resolution capillary Zone Electrophoresis for transferrin glycoform analysis associated with congenital disorders of glycosylation.
    2018
    Co-Authors: Tobler Micha, Caslavsky Jitka, Burda Patricie, Thormann Wolfgang
    Abstract:

    High-resolution capillary Zone Electrophoresis is used to assess the transferrin profile in serum of patients with eight different congenital disorders of glycosylation that represent type I, type II and mixed type I/II disorders. Capillary Zone Electrophoresis data are compared to patterns obtained by gel isoelectric focusing. The high-resolution capillary Zone Electrophoresis method is shown to represent an effective tool to assess the diversity of transferrin patterns. Hypoglycosylated disialo-, monosialo- and asialo-transferrin in type I cases can be distinguished from the corresponding underdesialylated transferrin glycoforms present in type II disorders. The latter can be separated from and are detected ahead of their corresponding hypoglycosylated forms of type I patients. Both types of glycoforms are detected in sera of mixed type I/II patients. The assay has the potential to be used as screening method for congenital disorders of glycosylation. It can be run with a few μL of serum when microvials are used. This article is protected by copyright. All rights reserved

  • High-resolution capillary Zone Electrophoresis for transferrin glycoform analysis associated with congenital disorders of glycosylation
    2018
    Co-Authors: Tobler Micha, Caslavsky Jitka, Burda Patricie, Thormann Wolfgang
    Abstract:

    High-resolution capillary Zone Electrophoresis is used to assess the transferrin profile in serum of patients with eight different congenital disorders of glycosylation that represent type I, type II, and mixed type I/II disorders. Capillary Zone Electrophoresis data are compared to patterns obtained by gel isoelectric focusing. The high-resolution capillary Zone Electrophoresis method is shown to represent an effective tool to assess the diversity of transferrin patterns. Hypoglycosylated disialo-, monosialo-, and asialo-transferrin in type I cases can be distinguished from the corresponding underdesialylated transferrin glycoforms present in type II disorders. The latter can be separated from and detected ahead of their corresponding hypoglycosylated forms of type I patients. Both types of glycoforms are detected in sera of mixed type I/II patients. The assay has the potential to be used as screening method for congenital disorders of glycosylation. It can be run with a few microliters of serum when microvials are used