1
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Wilson J, Bilbao A, Wang J, Liao YC, Velickovic D, Wojcik R, Passamonti M, Zhao R, Gargano AFG, Gerbasi VR, Pas̆a-Tolić L, Baker SE, Zhou M. Online Hydrophilic Interaction Chromatography (HILIC) Enhanced Top-Down Mass Spectrometry Characterization of the SARS-CoV-2 Spike Receptor-Binding Domain. Anal Chem 2022; 94:5909-5917. [PMID: 35380435 PMCID: PMC9003935 DOI: 10.1021/acs.analchem.2c00139] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2022] [Accepted: 03/25/2022] [Indexed: 12/13/2022]
Abstract
SARS-CoV-2 cellular infection is mediated by the heavily glycosylated spike protein. Recombinant versions of the spike protein and the receptor-binding domain (RBD) are necessary for seropositivity assays and can potentially serve as vaccines against viral infection. RBD plays key roles in the spike protein's structure and function, and thus, comprehensive characterization of recombinant RBD is critically important for biopharmaceutical applications. Liquid chromatography coupled to mass spectrometry has been widely used to characterize post-translational modifications in proteins, including glycosylation. Most studies of RBDs were performed at the proteolytic peptide (bottom-up proteomics) or released glycan level because of the technical challenges in resolving highly heterogeneous glycans at the intact protein level. Herein, we evaluated several online separation techniques: (1) C2 reverse-phase liquid chromatography (RPLC), (2) capillary zone electrophoresis (CZE), and (3) acrylamide-based monolithic hydrophilic interaction chromatography (HILIC) to separate intact recombinant RBDs with varying combinations of glycosylations (glycoforms) for top-down mass spectrometry (MS). Within the conditions we explored, the HILIC method was superior to RPLC and CZE at separating RBD glycoforms, which differ significantly in neutral glycan groups. In addition, our top-down analysis readily captured unexpected modifications (e.g., cysteinylation and N-terminal sequence variation) and low abundance, heavily glycosylated proteoforms that may be missed by using glycopeptide data alone. The HILIC top-down MS platform holds great potential in resolving heterogeneous glycoproteins for facile comparison of biosimilars in quality control applications.
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Affiliation(s)
- Jesse
W. Wilson
- Environmental
Molecular Sciences Laboratory, Pacific Northwest
National Laboratory, 3335 Innovation Boulevard, Richland, Washington 99354, United States
| | - Aivett Bilbao
- Environmental
Molecular Sciences Laboratory, Pacific Northwest
National Laboratory, 3335 Innovation Boulevard, Richland, Washington 99354, United States
| | - Juan Wang
- Biological
Sciences Division, Pacific Northwest National
Laboratories, 902 Battelle
Boulevard, Richland, Washington 99354, United States
| | - Yen-Chen Liao
- Environmental
Molecular Sciences Laboratory, Pacific Northwest
National Laboratory, 3335 Innovation Boulevard, Richland, Washington 99354, United States
| | - Dusan Velickovic
- Environmental
Molecular Sciences Laboratory, Pacific Northwest
National Laboratory, 3335 Innovation Boulevard, Richland, Washington 99354, United States
| | - Roza Wojcik
- National
Security Directorate, Pacific Northwest
National Laboratories, 902 Battelle Boulevard, Richland, Washington 99354, United States
| | - Marta Passamonti
- Centre
for Analytical Sciences Amsterdam, Amsterdam 1098 XH, The
Netherlands
- Van’t
Hoff Institute for Molecular Sciences, University
of Amsterdam, Amsterdam 1098 XH, The Netherlands
| | - Rui Zhao
- Environmental
Molecular Sciences Laboratory, Pacific Northwest
National Laboratory, 3335 Innovation Boulevard, Richland, Washington 99354, United States
| | - Andrea F. G. Gargano
- Centre
for Analytical Sciences Amsterdam, Amsterdam 1098 XH, The
Netherlands
- Van’t
Hoff Institute for Molecular Sciences, University
of Amsterdam, Amsterdam 1098 XH, The Netherlands
| | - Vincent R. Gerbasi
- Biological
Sciences Division, Pacific Northwest National
Laboratories, 902 Battelle
Boulevard, Richland, Washington 99354, United States
| | - Ljiljana Pas̆a-Tolić
- Environmental
Molecular Sciences Laboratory, Pacific Northwest
National Laboratory, 3335 Innovation Boulevard, Richland, Washington 99354, United States
| | - Scott E. Baker
- Environmental
Molecular Sciences Laboratory, Pacific Northwest
National Laboratory, 3335 Innovation Boulevard, Richland, Washington 99354, United States
| | - Mowei Zhou
- Environmental
Molecular Sciences Laboratory, Pacific Northwest
National Laboratory, 3335 Innovation Boulevard, Richland, Washington 99354, United States
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2
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Harrilal CP, Gandhi VD, Nagy G, Chen X, Buchanan MG, Wojcik R, Conant CR, Donor MT, Ibrahim YM, Garimella SVB, Smith RD, Larriba-Andaluz C. Measurement and Theory of Gas-Phase Ion Mobility Shifts Resulting from Isotopomer Mass Distribution Changes. Anal Chem 2021; 93:14966-14975. [PMID: 34726890 DOI: 10.1021/acs.analchem.1c01736] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The unanticipated discovery of recent ultra-high-resolution ion mobility spectrometry (IMS) measurements revealing that isotopomers─compounds that differ only in the isotopic substitution sites─can be separated has raised questions as to the physical basis for their separation. A study comparing IMS separations for two isotopomer sets in conjunction with theory and simulations accounting for ion rotational effects provides the first-ever prediction of rotation-mediated shifts. The simulations produce observable mobility shifts due to differences in gas-ion collision frequency and translational-to-rotational energy transfer. These differences can be attributed to distinct changes in the moment of inertia and center of mass between isotopomers. The simulations are in broad agreement with the observed experiments and consistent with relative mobility differences between isotopomers. These results provide a basis for refining IMS theory and a new foundation to obtain additional structural insights through IMS.
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Affiliation(s)
- Christopher P Harrilal
- Biological Sciences Division, Pacific Northwest National Laboratory, 902 Battelle Blvd, Richland, Washington 99354, United States
| | - Viraj D Gandhi
- Department of Mechanical Engineering, Purdue University, 585 Purdue Mall, West Lafayette, Indiana 47907, United States.,Department of Mechanical and Energy Engineering, IUPUI, 723 W. Michigan Street, Indianapolis, Indiana 46202, United States
| | - Gabe Nagy
- Chemistry Department, University of Utah, Salt Lake City, Utah 84112, United States
| | - Xi Chen
- Department of Mechanical Engineering, Purdue University, 585 Purdue Mall, West Lafayette, Indiana 47907, United States.,Department of Mechanical and Energy Engineering, IUPUI, 723 W. Michigan Street, Indianapolis, Indiana 46202, United States
| | - Michael G Buchanan
- Department of Mechanical and Energy Engineering, IUPUI, 723 W. Michigan Street, Indianapolis, Indiana 46202, United States
| | - Roza Wojcik
- Biological Sciences Division, Pacific Northwest National Laboratory, 902 Battelle Blvd, Richland, Washington 99354, United States
| | - Christopher R Conant
- Biological Sciences Division, Pacific Northwest National Laboratory, 902 Battelle Blvd, Richland, Washington 99354, United States
| | - Micah T Donor
- Biological Sciences Division, Pacific Northwest National Laboratory, 902 Battelle Blvd, Richland, Washington 99354, United States
| | - Yehia M Ibrahim
- Biological Sciences Division, Pacific Northwest National Laboratory, 902 Battelle Blvd, Richland, Washington 99354, United States
| | - Sandilya V B Garimella
- Biological Sciences Division, Pacific Northwest National Laboratory, 902 Battelle Blvd, Richland, Washington 99354, United States
| | - Richard D Smith
- Biological Sciences Division, Pacific Northwest National Laboratory, 902 Battelle Blvd, Richland, Washington 99354, United States
| | - Carlos Larriba-Andaluz
- Department of Mechanical and Energy Engineering, IUPUI, 723 W. Michigan Street, Indianapolis, Indiana 46202, United States
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3
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Wojcik R, Oxford TL, Melville A, Wright CW, Wright BW. Mapping Glyceride Species in Biodiesel by High-Temperature Gas Chromatography Combined with Chemical Ionization Mass Spectrometry. Anal Chem 2021; 93:14432-14439. [PMID: 34669385 DOI: 10.1021/acs.analchem.1c02474] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Accurate and comprehensive identification of residual glycerides in biodiesel is an important part of fuel characterization due to the impact of glycerides on the fuel physicochemical properties. However, analysis of bound glycerol in biodiesel samples faces challenges due to lack of readily available standards of structurally complex glyceride species in nontraditional biodiesel feedstocks and a risk of misannotation in the presence of impurities in gas chromatographic separations. Here, we evaluate methane and isobutane chemical ionization-single quadrupole mass spectrometry combined with high-temperature gas chromatography separations for mapping monoacylglycerols, diacylglycerols, and triacylglycerols in biodiesel. Unlike electron impact ionization, which produces mostly in-source fragments, isobutane chemical ionization spectra of tetramethylsilyl-derivatized monoacylglycerols and diacylglycerols are dominated by molecular ions and M-SiO(CH3)3+ ions, which provide important diagnostic information. We demonstrate the utility of isobutane chemical ionization in identifying structurally complex glycerolipid standards as well as species in biodiesel samples from different plant and animal feedstocks.
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Affiliation(s)
- Roza Wojcik
- National Security Directorate, Pacific Northwest National Laboratory, 902 Battelle Blvd., Richland, Washington 99352, United States
| | - Tessa L Oxford
- National Security Directorate, Pacific Northwest National Laboratory, 902 Battelle Blvd., Richland, Washington 99352, United States
| | - Angela Melville
- National Security Directorate, Pacific Northwest National Laboratory, 902 Battelle Blvd., Richland, Washington 99352, United States
| | - Cherylyn W Wright
- National Security Directorate, Pacific Northwest National Laboratory, 902 Battelle Blvd., Richland, Washington 99352, United States
| | - Bob W Wright
- National Security Directorate, Pacific Northwest National Laboratory, 902 Battelle Blvd., Richland, Washington 99352, United States
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4
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Wojcik R, Nagy G, Attah IK, Webb IK, Garimella SVB, Weitz KK, Hollerbach A, Monroe ME, Ligare MR, Nielson FF, Norheim RV, Renslow RS, Metz TO, Ibrahim YM, Smith RD. SLIM Ultrahigh Resolution Ion Mobility Spectrometry Separations of Isotopologues and Isotopomers Reveal Mobility Shifts due to Mass Distribution Changes. Anal Chem 2019; 91:11952-11962. [PMID: 31450886 PMCID: PMC7188075 DOI: 10.1021/acs.analchem.9b02808] [Citation(s) in RCA: 59] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
We report on separations of ion isotopologues and isotopomers using ultrahigh-resolution traveling wave-based Structures for Lossless Ion Manipulations with serpentine ultralong path and extended routing ion mobility spectrometry coupled to mass spectrometry (SLIM SUPER IMS-MS). Mobility separations of ions from the naturally occurring ion isotopic envelopes (e.g., [M], [M+1], [M+2], ... ions) showed the first and second isotopic peaks (i.e., [M+1] and [M+2]) for various tetraalkylammonium ions could be resolved from their respective monoisotopic ion peak ([M]) after SLIM SUPER IMS with resolving powers of ∼400-600. Similar separations were obtained for other compounds (e.g., tetrapeptide ions). Greater separation was obtained using argon versus helium drift gas, as expected from the greater reduced mass contribution to ion mobility described by the Mason-Schamp relationship. To more directly explore the role of isotopic substitutions, we studied a mixture of specific isotopically substituted (15N, 13C, and 2H) protonated arginine isotopologues. While the separations in nitrogen were primarily due to their reduced mass differences, similar to the naturally occurring isotopologues, their separations in helium, where higher resolving powers could also be achieved, revealed distinct additional relative mobility shifts. These shifts appeared correlated, after correction for the reduced mass contribution, with changes in the ion center of mass due to the different locations of heavy atom substitutions. The origin of these apparent mass distribution-induced mobility shifts was then further explored using a mixture of Iodoacetyl Tandem Mass Tag (iodoTMT) isotopomers (i.e., each having the same exact mass, but with different isotopic substitution sites). Again, the observed mobility shifts appeared correlated with changes in the ion center of mass leading to multiple monoisotopic mobilities being observed for some isotopomers (up to a ∼0.04% difference in mobility). These mobility shifts thus appear to reflect details of the ion structure, derived from the changes due to ion rotation impacting collision frequency or momentum transfer, and highlight the potential for new approaches for ion structural characterization.
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Affiliation(s)
- Roza Wojcik
- Biological Sciences Division, Pacific Northwest National Laboratory, Richland, Washington 99352, United States
| | - Gabe Nagy
- Biological Sciences Division, Pacific Northwest National Laboratory, Richland, Washington 99352, United States
| | - Isaac. K. Attah
- Biological Sciences Division, Pacific Northwest National Laboratory, Richland, Washington 99352, United States
| | - Ian K. Webb
- Department of Chemistry, Indiana University Purdue University Indianapolis, Indianapolis, Indiana 46202, United States
| | - Sandilya V. B. Garimella
- Biological Sciences Division, Pacific Northwest National Laboratory, Richland, Washington 99352, United States
| | - Karl K. Weitz
- Biological Sciences Division, Pacific Northwest National Laboratory, Richland, Washington 99352, United States
| | - Adam Hollerbach
- Biological Sciences Division, Pacific Northwest National Laboratory, Richland, Washington 99352, United States
| | - Matthew E. Monroe
- Biological Sciences Division, Pacific Northwest National Laboratory, Richland, Washington 99352, United States
| | - Marshall R. Ligare
- Physical Sciences Division, Pacific Northwest National Laboratory, Richland, Washington 99352, United States
| | - Felicity F. Nielson
- Biological Sciences Division, Pacific Northwest National Laboratory, Richland, Washington 99352, United States
| | - Randolph V. Norheim
- Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, Washington 99352, United States
| | - Ryan S. Renslow
- Biological Sciences Division, Pacific Northwest National Laboratory, Richland, Washington 99352, United States
| | - Thomas O. Metz
- Biological Sciences Division, Pacific Northwest National Laboratory, Richland, Washington 99352, United States
| | - Yehia M. Ibrahim
- Biological Sciences Division, Pacific Northwest National Laboratory, Richland, Washington 99352, United States
| | - Richard D. Smith
- Biological Sciences Division, Pacific Northwest National Laboratory, Richland, Washington 99352, United States
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5
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Wu H, Yi L, Wojcik R, Shi T, Tang K. A separation voltage polarity switching method for higher sample loading capacity and better separation resolution in transient capillary isotachophoresis separation. Analyst 2019; 144:454-462. [PMID: 30444223 DOI: 10.1039/c8an01779d] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
A separation voltage polarity switching transient capillary isotachophoresis (PS-tCITP) was developed to overcome a major sample loading volume limitation in transient capillary isotachophoresis (tCITP). The fundamental idea of PS-tCITP is to let sample ions move back and forth in a separation capillary during their initial isotachophoresis focusing stage by switching the polarity of the separation voltage, in order to both increase the sample loading volume and improve the separation efficiency as compared to the conventional tCITP method. The experimental evaluation of the novel PS-tCITP method by using two peptide standards at 2 μM concentration showed that the maximum sample loading volume could be increased from 45% of the total separation capillary volume in tCITP to 70% in PS-tCITP, which resulted in a more than 1.5 fold increase in the peptide peak intensity at a given length/volume of the separation capillary. Due to the consecutive focusing of sample volume from each polarity switching of the separation voltage, the separation time window at a given sample loading volume was also increased significantly in PS-tCITP as compared to tCITP. Experiment comparison between tCITP and PS-tCITP at 45% sample loading volume using the same setup showed that the migration time difference between the two peptide peaks increased from 0.3 min in tCITP to 0.363 min in PS-tCITP with similar peak widths and heights, resulting in roughly a 21% improvement in separation resolution. The performance advantages of PS-tCITP separation over tCITP separation were further verified by using a mixture of six peptide standards.
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Affiliation(s)
- Huanming Wu
- Faculty of Electrical Engineering and Computer Science, Ningbo University, Ningbo 315211, P. R. China
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6
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Chau VM, Engeln JT, Axelrath S, Khatter SJ, Kwon R, Melton MA, Reinsvold MC, Staley VM, To J, Tanabe KJ, Wojcik R. Beyond the Chief Complaint: Our Patients' Worries. J Med Humanit 2017; 38:541-547. [PMID: 28975579 DOI: 10.1007/s10912-017-9479-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Fourth-year medical students at the University of Colorado School of Medicine distributed cards to patients in the emergency department asking, "What Worries You Most?" The patients' responses provided insight about their most pressing concerns, often unrelated to their "chief complaints."
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Affiliation(s)
- V M Chau
- Gold Humanism Honor Society, Class of 2017, University of Colorado School of Medicine, Aurora, CO, USA.
| | - J T Engeln
- Gold Humanism Honor Society, Class of 2017, University of Colorado School of Medicine, Aurora, CO, USA
| | - S Axelrath
- Gold Humanism Honor Society, Class of 2017, University of Colorado School of Medicine, Aurora, CO, USA
| | - S J Khatter
- Gold Humanism Honor Society, Class of 2017, University of Colorado School of Medicine, Aurora, CO, USA
| | - R Kwon
- Gold Humanism Honor Society, Class of 2017, University of Colorado School of Medicine, Aurora, CO, USA
| | - M A Melton
- Gold Humanism Honor Society, Class of 2017, University of Colorado School of Medicine, Aurora, CO, USA
| | - M C Reinsvold
- Gold Humanism Honor Society, Class of 2017, University of Colorado School of Medicine, Aurora, CO, USA
| | - V M Staley
- Gold Humanism Honor Society, Class of 2017, University of Colorado School of Medicine, Aurora, CO, USA
| | - J To
- Gold Humanism Honor Society, Class of 2017, University of Colorado School of Medicine, Aurora, CO, USA
| | - K J Tanabe
- Gold Humanism Honor Society, Class of 2017, University of Colorado School of Medicine, Aurora, CO, USA
| | - R Wojcik
- Gold Humanism Honor Society, Class of 2017, University of Colorado School of Medicine, Aurora, CO, USA
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7
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Zheng X, Wojcik R, Zhang X, Ibrahim YM, Burnum-Johnson KE, Orton DJ, Monroe ME, Moore RJ, Smith RD, Baker ES. Coupling Front-End Separations, Ion Mobility Spectrometry, and Mass Spectrometry For Enhanced Multidimensional Biological and Environmental Analyses. Annu Rev Anal Chem (Palo Alto Calif) 2017; 10:71-92. [PMID: 28301728 PMCID: PMC5627998 DOI: 10.1146/annurev-anchem-061516-045212] [Citation(s) in RCA: 67] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
Ion mobility spectrometry (IMS) is a widely used analytical technique for rapid molecular separations in the gas phase. Though IMS alone is useful, its coupling with mass spectrometry (MS) and front-end separations is extremely beneficial for increasing measurement sensitivity, peak capacity of complex mixtures, and the scope of molecular information available from biological and environmental sample analyses. In fact, multiple disease screening and environmental evaluations have illustrated that the IMS-based multidimensional separations extract information that cannot be acquired with each technique individually. This review highlights three-dimensional separations using IMS-MS in conjunction with a range of front-end techniques, such as gas chromatography, supercritical fluid chromatography, liquid chromatography, solid-phase extractions, capillary electrophoresis, field asymmetric ion mobility spectrometry, and microfluidic devices. The origination, current state, various applications, and future capabilities of these multidimensional approaches are described in detail to provide insight into their uses and benefits.
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Affiliation(s)
- Xueyun Zheng
- Earth and Biological Sciences Directorate, Pacific Northwest National Laboratory, Richland, Washington 99352;
| | - Roza Wojcik
- Earth and Biological Sciences Directorate, Pacific Northwest National Laboratory, Richland, Washington 99352;
| | - Xing Zhang
- Skaggs School of Pharmacy and Pharmaceutical Sciences, Anschutz Medical Campus, University of Colorado, Denver, Colorado 80045
| | - Yehia M Ibrahim
- Earth and Biological Sciences Directorate, Pacific Northwest National Laboratory, Richland, Washington 99352;
| | - Kristin E Burnum-Johnson
- Earth and Biological Sciences Directorate, Pacific Northwest National Laboratory, Richland, Washington 99352;
| | - Daniel J Orton
- Earth and Biological Sciences Directorate, Pacific Northwest National Laboratory, Richland, Washington 99352;
| | - Matthew E Monroe
- Earth and Biological Sciences Directorate, Pacific Northwest National Laboratory, Richland, Washington 99352;
| | - Ronald J Moore
- Earth and Biological Sciences Directorate, Pacific Northwest National Laboratory, Richland, Washington 99352;
| | - Richard D Smith
- Earth and Biological Sciences Directorate, Pacific Northwest National Laboratory, Richland, Washington 99352;
| | - Erin S Baker
- Earth and Biological Sciences Directorate, Pacific Northwest National Laboratory, Richland, Washington 99352;
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8
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Ibrahim YM, Garimella SVB, Prost SA, Wojcik R, Norheim RV, Baker ES, Rusyn I, Smith RD. Development of an Ion Mobility Spectrometry-Orbitrap Mass Spectrometer Platform. Anal Chem 2016; 88:12152-12160. [PMID: 28193022 PMCID: PMC6211177 DOI: 10.1021/acs.analchem.6b03027] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Complex samples benefit from multidimensional measurements where higher resolution enables more complete characterization of biological and environmental systems. To address this challenge, we developed a drift tube-based ion mobility spectrometry-Orbitrap mass spectrometer (IMS-Orbitrap MS) platform. To circumvent the time scale disparity between the fast IMS separation and the much slower Orbitrap MS acquisition, we utilized a dual gate and pseudorandom sequences to multiplex the injection of ions and allow operation in signal averaging (SA), single multiplexing (SM), and double multiplexing (DM) IMS modes to optimize the signal-to-noise ratio of the measurements. For the SM measurements, a previously developed algorithm was used to reconstruct the IMS data. A new algorithm was developed for the DM analyses involving a two-step process that first recovers the SM data and then decodes the SM data. The algorithm also performs multiple refining procedures to minimize demultiplexing artifacts. The new IMS-Orbitrap MS platform was demonstrated by the analysis of proteomic and petroleum samples, where the integration of IMS and high mass resolution proved essential for accurate assignment of molecular formulas.
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Affiliation(s)
- Yehia M. Ibrahim
- Biological Sciences Division, Pacific Northwest National Laboratory, P.O. Box 999, Richland, Washington 99352, United States
| | - Sandilya V. B. Garimella
- Biological Sciences Division, Pacific Northwest National Laboratory, P.O. Box 999, Richland, Washington 99352, United States
| | - Spencer A. Prost
- Biological Sciences Division, Pacific Northwest National Laboratory, P.O. Box 999, Richland, Washington 99352, United States
| | - Roza Wojcik
- Biological Sciences Division, Pacific Northwest National Laboratory, P.O. Box 999, Richland, Washington 99352, United States
| | - Randolph V. Norheim
- Biological Sciences Division, Pacific Northwest National Laboratory, P.O. Box 999, Richland, Washington 99352, United States
| | - Erin S. Baker
- Biological Sciences Division, Pacific Northwest National Laboratory, P.O. Box 999, Richland, Washington 99352, United States
| | - Ivan Rusyn
- Department of Veterinary Integrative Biosciences, Texas A&M University, College Station, Texas 77843, United States
| | - Richard D. Smith
- Biological Sciences Division, Pacific Northwest National Laboratory, P.O. Box 999, Richland, Washington 99352, United States
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9
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Sun L, Zhu G, Yan X, Zhang Z, Wojcik R, Champion MM, Dovichi NJ. Capillary zone electrophoresis for bottom-up analysis of complex proteomes. Proteomics 2015; 16:188-96. [PMID: 26508368 DOI: 10.1002/pmic.201500339] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2015] [Revised: 09/30/2015] [Accepted: 10/22/2015] [Indexed: 12/22/2022]
Abstract
Capillary zone electrophoresis (CZE) is emerging as a useful tool in proteomic analysis. Interest arises from dramatic improvements in performance that result from improvements in the background electrolyte used for the separation, the incorporation of advanced sample injection methods, the development of robust and sensitive electrospray interfaces, and the coupling with Orbitrap mass spectrometers with high resolution and sensitivity. The combination of these technologies produces performance that is rapidly approaching the performance of UPLC-based methods for microgram samples and exceeds the performance of UPLC-based methods for mid- to low nanogram samples. These systems now produce over 10 000 peptide IDs in a single 100-min analysis of the HeLa proteome.
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Affiliation(s)
- Liangliang Sun
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN, USA
| | - Guijie Zhu
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN, USA
| | - Xiaojing Yan
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN, USA
| | - Zhenbin Zhang
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN, USA
| | - Roza Wojcik
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN, USA
| | - Matthew M Champion
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN, USA
| | - Norman J Dovichi
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN, USA
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10
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Schiavone NM, Sarver SA, Sun L, Wojcik R, Dovichi NJ. High speed capillary zone electrophoresis-mass spectrometry via an electrokinetically pumped sheath flow interface for rapid analysis of amino acids and a protein digest. J Chromatogr B Analyt Technol Biomed Life Sci 2015; 991:53-8. [PMID: 25913424 DOI: 10.1016/j.jchromb.2015.04.001] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2015] [Revised: 04/01/2015] [Accepted: 04/03/2015] [Indexed: 12/22/2022]
Abstract
While capillary zone electrophoresis (CZE) has been used to produce very rapid and efficient separations, coupling these high-speed separations with mass spectrometry (MS) has been challenging. Now, with much faster and sensitive mass spectrometers, it is possible to take full advantage of the CZE speed and reconstruct the fast migrating peaks. Here are three high-speed CZE-MS analyses via an electrokinetically pumped sheath-flow interface. The first separation demonstrates CZE-ESI-MS of an amino acid mixture with a 2-min separation, >50,000 theoretical plates, low micromolar concentration detection limits, and subfemtomole mass detection limits (LTQ XL mass spectrometer). The second separation with our recently improved third-generation CE-MS interface illustrates a 20 amino acid separation in ∼7min with an average over 200,000 plate counts, and results in almost-baseline resolution of structural isomers, leucine and isoleucine. The third separation is of a BSA digest with a reproducible CZE separation and mass spectrometry detection in 2min. CZE-MS/MS analysis of the BSA digest identified 31 peptides, produced 52% sequence coverage, and generated a peak capacity of ∼40 across the 1-min separation window (Q-Exactive mass spectrometer).
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Affiliation(s)
- Nicole M Schiavone
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN 46556, USA
| | - Scott A Sarver
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN 46556, USA
| | - Liangliang Sun
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN 46556, USA
| | - Roza Wojcik
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN 46556, USA
| | - Norman J Dovichi
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN 46556, USA.
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11
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Sun L, Li Y, Champion MM, Zhu G, Wojcik R, Dovichi NJ. Capillary zone electrophoresis-multiple reaction monitoring from 100 pg of RAW 264.7 cell lysate digest. Analyst 2013; 138:3181-8. [PMID: 23591184 DOI: 10.1039/c3an00287j] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Capillary zone electrophoresis-multiple/single reaction monitoring (CZE-MRM/SRM), which employed an electrokinetically driven sheath-flow electrospray interface, was used for the rapid and highly sensitive detection of protein analytes in complex tryptic digests. MRM channels were developed against a commercial exponential mixture of bovine proteins. Five proteins spanning four orders of magnitude concentration range were confidently detected from only 2.5 ng of the digest mixture; the mass detection limits (S/N = 3) of two detected proteins, alpha-casein and glutamate dehydrogenase were about 600 zmol and 30 amol, respectively. This technique was then applied to a RAW 264.7 cell lysate digest. Three proteins were confidently and reproducibly detected from 100 pg of this digest. The sample amount corresponds to the approximate protein content from a single cell, which suggests that CZE-MRM may be a useful analytical tool in chemical cytometry. In addition to providing highly sensitive detection of proteins in complex mixtures, this system is highly rapid; migration time of the protein digests was less than 10 min.
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Affiliation(s)
- Liangliang Sun
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN 46556, USA
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12
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Mou S, Sun L, Wojcik R, Dovichi NJ. Coupling immobilized alkaline phosphatase-based automated diagonal capillary electrophoresis to tandem mass spectrometry for phosphopeptide analysis. Talanta 2013; 116:985-90. [PMID: 24148505 DOI: 10.1016/j.talanta.2013.08.001] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2013] [Accepted: 08/01/2013] [Indexed: 10/26/2022]
Abstract
Automated diagonal capillary electrophoresis is a two-dimensional separation method that incorporates an immobilized enzyme reactor at the distal end of the first capillary and employs identical electrophoretic separation modes in both dimensions. Components undergo a preliminary separation in the first capillary. Fractions are parked in the reactor where some components undergo transformation. The fractions are then periodically transferred to the second capillary and replaced by the next components in the sample. Components that are not modified by the reactor will have identical mobility in both dimensions and fall on the diagonal of a reconstructed two-dimensional electropherogram, while analyte that undergoes modification will fall off the diagonal. In this study, alkaline phosphatase was immobilized in a monolithic reactor. An LTQ-Orbitrap Velos mass spectrometer was used to monitor analytes as they migrated from the second capillary. The system was used to characterize the phosphorylation status of a tryptic digest of α-casein in a background prepared from a 22-fold excess of the tryptic digest of bovine serum albumin. 120 fractions underwent automated treatment in the alkaline phosphatase reactor and separation in the second dimension capillary for over 40 min; nine phosphorylated α-casein peptides that produced 20 different phosphorylation states were detected with high confidence.
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Affiliation(s)
- Si Mou
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN 46556, USA
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13
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Sun L, Zhu G, Li Y, Wojcik R, Yang P, Dovichi NJ. CZE-ESI-MS/MS system for analysis of subnanogram amounts of tryptic digests of a cellular homogenate. Proteomics 2012; 12:3013-9. [PMID: 22888077 DOI: 10.1002/pmic.201200100] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2012] [Revised: 06/14/2012] [Accepted: 06/18/2012] [Indexed: 12/15/2022]
Abstract
We report the performance of capillary zone electrophoresis coupled with an electrokinetically pumped electrospray interface and an Orbitrap-Velos mass spectrometer for high sensitivity protein analysis. We first investigated the system for quantitation of the tryptic digest of BSA. The system produced outstanding linearity with respect to peak height, number of peptide IDs, and spectral counts across the range of 12 nM to 750 nM (60 amol to 3.5 fmol) of BSA injected. One peptide produced a detection limit of 0.3 nM (1.5 amol) injected. We also analyzed 700 pg of a tryptic digest prepared from a RAW264.7 cell lysate; ten proteins were identified in triplicate analyses after filtering the data with peptide confidence value as high. This sample size corresponds to the protein content of approximately ten eukaryotic cells.
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Affiliation(s)
- Liangliang Sun
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN 46556, USA
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14
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Zhu G, Sun L, Wojcik R, Kernaghan D, McGivney JB, Dovichi NJ. A rapid cIEF–ESI–MS/MS method for host cell protein analysis of a recombinant human monoclonal antibody. Talanta 2012; 98:253-6. [DOI: 10.1016/j.talanta.2012.07.017] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2012] [Revised: 07/05/2012] [Accepted: 07/06/2012] [Indexed: 02/07/2023]
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15
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Li Y, Wojcik R, Dovichi NJ, Champion MM. Quantitative multiple reaction monitoring of peptide abundance introduced via a capillary zone electrophoresis-electrospray interface. Anal Chem 2012; 84:6116-21. [PMID: 22690842 PMCID: PMC3674544 DOI: 10.1021/ac300926h] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
We demonstrate the use of capillary zone electrophoresis with an electrokinetic sheath-flow electrospray interface coupled to a triple-quadrupole mass spectrometer for the accurate and precise quantification of Leu-enkephalin in a complex mixture using multiple-reaction monitoring (MRM). Assay time is <6 min, with no re-equilibration required between runs. A standard curve of Leu-enkephalin was performed in the presence of a background tryptic digest of bovine albumin. We demonstrate reasonably reproducible peak heights (21% relative standard deviation), retention times (better than 1% relative standard deviation), and robust electrospray quality. Our limit of detection (3σ) was 60 pM, which corresponds to the injection of 335 zmol of peptide. This is a 10-20-fold improvement in mass sensitivity than we have obtained by nano HPLC/MRM and substantially better than reported for LC/MS/MS. Further quantification was performed in the presence of stable-isotope-labeled versions of the peptides; under these conditions, linearity was observed across nearly 4 orders of magnitude. The concentration detection limit was 240 pM for the stable-isotope-labeled quantification.
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Affiliation(s)
- Yihan Li
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556, United States
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16
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Tomayao A, Yoon IK, Tac-an I, Macasocol D, Obidas D, Ygona S, Coberly J, Wojcik R, Alera M, Velasco J, Fernandez T. Implementation of SMS fever surveillance in the Philippines. Int J Infect Dis 2012. [DOI: 10.1016/j.ijid.2012.05.332] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
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17
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Li Y, Champion MM, Sun L, DiGiuseppe Champion PA, Wojcik R, Dovichi NJ. Capillary zone electrophoresis-electrospray ionization-tandem mass spectrometry as an alternative proteomics platform to ultraperformance liquid chromatography-electrospray ionization-tandem mass spectrometry for samples of intermediate complexity. Anal Chem 2012; 84:1617-22. [PMID: 22182061 PMCID: PMC3277681 DOI: 10.1021/ac202899p] [Citation(s) in RCA: 117] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
We demonstrate the use of capillary zone electrophoresis with an electrokinetically pumped sheath-flow electrospray interface for the analysis of a tryptic digest of a sample of intermediate protein complexity, the secreted protein fraction of Mycobacterium marinum. For electrophoretic analysis, 11 fractions were generated from the sample using reverse-phase liquid chromatography; each fraction was analyzed by CZE-ESI-MS/MS, and 334 peptides corresponding to 140 proteins were identified in 165 min of mass spectrometer time at 95% confidence (FDR < 0.15%). In comparison, 388 peptides corresponding to 134 proteins were identified in 180 min of mass spectrometer time by triplicate UPLC-ESI-MS/MS analyses, each using 250 ng of the unfractionated peptide mixture, at 95% confidence (FDR < 0.15%). Overall, 62% of peptides identified in CZE-ESI-MS/MS and 67% in UPLC-ESI-MS/MS were unique. CZE-ESI-MS/MS favored basic and hydrophilic peptides with low molecular masses. Combining the two data sets increased the number of unique peptides by 53%. Our approach identified more than twice as many proteins as the previous record for capillary electrophoresis proteome analysis. CE-ESI-MS/MS is a useful tool for the analysis of proteome samples of intermediate complexity.
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Affiliation(s)
- Yihan Li
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN USA 46556
- Department of Chemistry, University of Washington, Seattle WA USA 98195
| | - Matthew M. Champion
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN USA 46556
| | - Liangliang Sun
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN USA 46556
| | | | - Roza Wojcik
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN USA 46556
| | - Norman J. Dovichi
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN USA 46556
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Wojcik R, Li Y, Maccoss MJ, Dovichi NJ. Capillary electrophoresis with Orbitrap-Velos mass spectrometry detection. Talanta 2012; 88:324-9. [PMID: 22265506 PMCID: PMC3266533 DOI: 10.1016/j.talanta.2011.10.048] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2011] [Revised: 10/20/2011] [Accepted: 10/21/2011] [Indexed: 01/08/2023]
Abstract
Capillary electrophoresis can provide fast and efficient separations of peptides. However, the high speed separation and limited loading capacity of capillary electrophoresis requires the use of a fast and sensitive detector. While laser-induced fluorescence provides exquisite sensitivity and millisecond response time, it inherently generates a low information content signal. In contrast, mass spectrometry provides an information rich signal that is attractive for peptide analysis. The recently introduced Velos-Orbitrap mass spectrometer is capable of fast and sensitive tandem MS acquisition and simultaneous high accuracy MS acquisition, which is well suited for coupling with fast and efficient separation methods for peptide analysis. We evaluated this instrument as a detector for peptide separation by capillary electrophoresis. In MS mode, we observed low attomole detection limits for a number of peptides in a tryptic digest of standard proteins with high mass resolution (30,000 at m/z 400). The response time of the Orbitrap at this resolution was ∼0.70s, which was adequate to reconstruct the peak shape and area of our electrophoretic peaks. The linear ion-trap successfully recorded tandem MS spectra of tryptic peptides at 20 nM concentration.
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Affiliation(s)
- Roza Wojcik
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN 46556, United States
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Li Y, Wojcik R, Dovichi NJ. A replaceable microreactor for on-line protein digestion in a two-dimensional capillary electrophoresis system with tandem mass spectrometry detection. J Chromatogr A 2010; 1218:2007-11. [PMID: 21030030 DOI: 10.1016/j.chroma.2010.10.013] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2010] [Revised: 09/30/2010] [Accepted: 10/04/2010] [Indexed: 01/15/2023]
Abstract
We describe a two-dimensional capillary electrophoresis system that incorporates a replaceable enzymatic microreactor for on-line protein digestion. In this system, trypsin is immobilized on magnetic beads. At the start of each experiment, old beads are flushed to waste and replaced with a fresh plug of beads, which is captured by a pair of magnets at the distal tip of the first capillary. For analysis, proteins are separated in the first capillary. A fraction is then parked in the reactor to create peptides. Digested peptides are periodically transferred to the second capillary for separation; a fresh protein fraction is simultaneously moved to the reactor for digestion. An electrospray interface is used to introduce peptides into a mass spectrometer for analysis. This procedure is repeated for several dozen fractions under computer control. The system was demonstrated by the separation and digestion of insulin chain b oxidized and β-casein as model proteins.
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Affiliation(s)
- Yihan Li
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN 46556, USA
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20
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Wojcik R, Dada OO, Sadilek M, Dovichi NJ. Simplified capillary electrophoresis nanospray sheath-flow interface for high efficiency and sensitive peptide analysis. Rapid Commun Mass Spectrom 2010; 24:2554-60. [PMID: 20740530 DOI: 10.1002/rcm.4672] [Citation(s) in RCA: 161] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
We report a simple nanospray sheath-flow interface for capillary electrophoresis. This interface relies on electrokinetic flow to drive both the separation and the electrospray; no mechanical pump is used for the sheath flow. This system was interfaced with an LCQ mass spectrometer. The best results were observed with a 2-microm diameter emitter tip and a 1-mm spacing between the separation capillary tip and the emitter tip. Under these conditions, mass detection limits (3sigma) of 100 amol were obtained for insulin receptor fragment 1142-1153. The separation efficiency exceeded 200,000 plates for this compound. The relative standard deviation generated during continual infusion of a 50 microM solution of angiotensin II was 2% for the total ion count and 3% for the extracted ion count over a 40-min period. Finally, the interface was also demonstrated for negative ion mode.
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Affiliation(s)
- Roza Wojcik
- Department of Chemistry, University of Washington, Seattle, WA 98195-1700, USA
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21
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Wojcik R, Vannatta M, Dovichi NJ. Automated enzyme-based diagonal capillary electrophoresis: application to phosphopeptide characterization. Anal Chem 2010; 82:1564-7. [PMID: 20099889 DOI: 10.1021/ac100029u] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Diagonal capillary electrophoresis is a form of two-dimensional capillary electrophoresis that employs identical separation modes in each dimension. The distal end of the first capillary incorporates an enzyme-based microreactor. Analytes that are not modified by the reactor will have identical migration times in the two capillaries and will generate spots that fall on the diagonal in a reconstructed two-dimensional electropherogram. Analytes that undergo enzymatic modification in the reactor will have different migration times in the second capillary and will generate spots that fall off the diagonal in the electropherogram. We demonstrate the system with immobilized alkaline phosphatase to monitor the phosphorylation status of a mixture of peptides. This enzyme-based diagonal capillary electrophoresis assay appears to be generalizable; any post-translational modification can be detected as long as an immobilized enzyme is available that reacts with the modification under electrophoretic conditions.
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Affiliation(s)
- Roza Wojcik
- Department of Chemistry, University of Washington, Seattle, Washington 98195-1700, USA
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Turner EH, Dickerson JA, Ramsay LM, Swearingen KE, Wojcik R, Dovichi NJ. Reaction of fluorogenic reagents with proteins III. Spectroscopic and electrophoretic behavior of proteins labeled with Chromeo P503. J Chromatogr A 2008; 1194:253-6. [PMID: 18482729 PMCID: PMC2566543 DOI: 10.1016/j.chroma.2008.04.046] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2008] [Revised: 04/16/2008] [Accepted: 04/18/2008] [Indexed: 11/15/2022]
Abstract
The spectroscopic and electrophoretic properties of proteins labeled with Chromeo P503 were investigated. Its photobleaching characteristics were determined by continually infusing Chromeo P503-labeled alpha-lactalbumin into a sheath-flow cuvette and monitored fluorescence as a function of laser power. The labeled protein is relatively photo-labile with an optimum excitation power of about 2 mW. The unreacted reagent is weakly fluorescent but present at much higher concentration than the labeled protein. The unreacted reagent undergoes photobleaching at a laser power more than an order of magnitude higher than the labeled protein. One-dimensional capillary electrophoresis analysis of Chromeo P503-labeled alpha-lactalbumin produced concentration detection limits (3sigma) of 12 pM and mass detection limits of 0.7 zmol, but with modest theoretical plate counts of 17,000. The reagent was employed for the two-dimensional capillary electrophoresis analysis of a homogenate prepared from a Barrett's esophagus cell line; the separation quality is similar to that produced by 3-(2-furoyl)quinoline-2-carboxaldehyde (FQ), a more commonly used reagent.
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Affiliation(s)
- Emily H. Turner
- Department of Chemistry, University of Washington, Seattle, WA 98195, USA
| | - Jane A. Dickerson
- Department of Chemistry, University of Washington, Seattle, WA 98195, USA
| | - Lauren M. Ramsay
- Department of Chemistry, University of Washington, Seattle, WA 98195, USA
| | | | - Roza Wojcik
- Department of Chemistry, University of Washington, Seattle, WA 98195, USA
| | - Norman J. Dovichi
- Department of Chemistry, University of Washington, Seattle, WA 98195, USA
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23
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Wojcik R, Swearingen KE, Dickerson JA, Turner EH, Ramsay LM, Dovichi NJ. Reaction of fluorogenic reagents with proteins I. Mass spectrometric characterization of the reaction with 3-(2-furoyl)quinoline-2-carboxaldehyde, Chromeo P465, and Chromeo P503. J Chromatogr A 2008; 1194:243-8. [PMID: 18479688 PMCID: PMC2518533 DOI: 10.1016/j.chroma.2008.04.042] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2008] [Revised: 04/10/2008] [Accepted: 04/17/2008] [Indexed: 10/22/2022]
Abstract
3-(2-Furoyl)quinoline-2-carboxaldehyde (FQ), Chromeo P465, and Chromeo P503 are weakly fluorescent reagents that react with primary amines to produce fluorescent products. We studied the reaction of these reagents with alpha-lactalbumin by mass spectrometry. The reaction generated a set of products by the addition of one or more labels to the protein. At room temperature, the reaction was an order of magnitude faster with the Chromeo reagents than with FQ; however, the steady-state labeling efficiency was a factor of two higher for FQ compared with the Chromeo reagents. The relative abundance of the products with FQ usually followed a binomial distribution, which suggests that the labeling sites were uniformly accessible to this reagent. In contrast, the distribution of reaction products with the Chromeo reagents did not follow a binomial distribution for reactions performed in the absence of sodium dodecyl sulfate (SDS); it appears that the protein labeled with the Chromeo reagents refolded into a relatively stable secondary structure that hid some reactive sites. The reaction with the Chromeo reagent did follow the binomial distribution if the protein underwent treatment with 1% SDS at 95 degrees C for 5 min, which apparently disrupts the protein's secondary structure and allowed uniform access to all labeling sites. Chromeo 503 labeled seven of the 13 primary amines in denatured alpha-lactalbumin.
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Affiliation(s)
- Roza Wojcik
- Department of Chemistry, University of Washington, Box 351700, Seattle, WA 98195-1700, USA
| | - Kristian E. Swearingen
- Department of Chemistry, University of Washington, Box 351700, Seattle, WA 98195-1700, USA
| | - Jane A. Dickerson
- Department of Chemistry, University of Washington, Box 351700, Seattle, WA 98195-1700, USA
| | - Emily H. Turner
- Department of Chemistry, University of Washington, Box 351700, Seattle, WA 98195-1700, USA
| | - Lauren M. Ramsay
- Department of Chemistry, University of Washington, Box 351700, Seattle, WA 98195-1700, USA
| | - Norman J. Dovichi
- Department of Chemistry, University of Washington, Box 351700, Seattle, WA 98195-1700, USA
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24
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Swearingen KE, Dickerson JA, Turner EH, Ramsay LM, Wojcik R, Dovichi NJ. Reaction of fluorogenic reagents with proteins II: capillary electrophoresis and laser-induced fluorescence properties of proteins labeled with Chromeo P465. J Chromatogr A 2008; 1194:249-52. [PMID: 18479693 DOI: 10.1016/j.chroma.2008.04.047] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2008] [Revised: 04/16/2008] [Accepted: 04/18/2008] [Indexed: 11/18/2022]
Abstract
The fluorogenic reagent Chromeo P465 is considered for the analysis of proteins by capillary electrophoresis with laser-induced fluorescence detection. The reagent was first used to label alpha-lactalbumin; the product was analyzed by capillary zone electrophoresis in a sub-micellar sodium dodecyl sulfate (SDS) buffer. The product generated a set of equally spaced but poorly resolved peaks that formed a broad envelope with a net mobility of 4 x 10(-4)cm(2) V(-1) s(-1). The components of the envelope were presumably protein that had reacted with different numbers of labels. The mobility of these components decreased by roughly 1% with the addition of each label. The signal increased linearly from 1.0 nM to 100 nM alpha-lactalbumin (r(2)=0.99), with a 3sigma detection limit of 70 pM. We then considered the separation of a mixture of ovalbumin, alpha-chymotrypsinogen A, and alpha-lactalbumin labeled with Chromeo P465; unfortunately, baseline resolution was not achieved with a borax/SDS buffer. Better resolution was achieved with N-cyclohexyl-2-aminoethanesulfonic acid/Tris/SDS/dextran capillary sieving electrophoresis; however, dye interactions with this buffer system produced a less than ideal blank.
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Affiliation(s)
- Kristian E Swearingen
- Department of Chemistry, University of Washington, Box 351700, Seattle, WA 98195-1700, USA
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Abstract
OBJECTIVE The objective of this study was to determine whether the preinjury condition of anticoagulation had an adverse impact on patients sustaining injury. METHODS A retrospective analysis was performed for prospectively collected registry data from 1995-2000 from all accredited trauma centers in Pennsylvania. The registry was queried for all trauma patients who had anticoagulation therapy as a preinjury condition (PIC). This group served as our experimental cohort. A control cohort (not having warfarin therapy as a PIC) was developed using case-matching techniques for age, sex, Glasgow Coma Scale (GCS), Injury Severity Score (ISS), A Severity Characterization of Trauma (ASCOT) score, and in the head injured patients, International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) diagnoses. Head and non-head injured patients were evaluated separately. The cohorts were examined for 28-day mortality, intensive care unit length of stay (ICU-LOS), hospital length of stay (HOS-LOS), PICs, occurrences, discharge destinations, and functional status at discharge. Chi2 and Student's t test were used to evaluate the data; p values < 0.05 were considered significant. RESULTS Two thousand nine hundred forty-two patients were available for analysis. The prevalence of PICs was significantly greater in the warfarin group for both the head and non-head injured populations (p < 0.003 and p < 0.0001, respectively). The incidence of occurrences in the non-head injured population was statistically higher for the warfarin patients (p < 0.001), but showed no difference in the head injured group regardless of warfarin use (p = 0.15). Functional status at discharge demonstrated no clinically significant difference between the warfarin and non-warfarin groups in both head and non-head injured populations. There was no difference in discharge destination in the head injured population; however, in the non-head injured population a greater percentage of non-warfarin patients was discharged to home when compared with the warfarin patients. CONCLUSION Our data suggest that the PIC of anticoagulation with warfarin does not adversely impact mortality or LOS outcomes in both head and non-head injured patients. In non-head injured patients, however, the occurrence rates and discharge destination were different. More research needs to be done to determine whether this is related to anticoagulation or other reasons (i.e., number of PICs). These data should be used when weighing risk/benefit ratios of prescribing chronic anticoagulation.
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Affiliation(s)
- R Wojcik
- Department of Surgery, Lehigh Valley Hospital, Allentown, Pennsylvania 18105-1556, USA
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26
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Raylman RR, Majewski S, Weisenberger AG, Popov V, Wojcik R, Kross B, Schreiman JS, Bishop HA. Positron emission mammography-guided breast biopsy. J Nucl Med 2001; 42:960-6. [PMID: 11390563] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/20/2023] Open
Abstract
UNLABELLED Positron emission mammography (PEM) is a technique to obtain planar images of the breast for detection of potentially cancerous, radiotracer-avid tumors. To increase the diagnostic accuracy of this method, use of minimally invasive methods (e.g., core biopsy) may be desirable for obtaining tissue samples from lesions detected with PEM. The purpose of this study was to test the capabilities of a novel method for performing PEM-guided stereotactic breast biopsies. METHODS The PEM system consisted of 2 square (10 x 10 cm) arrays of discrete scintillator crystals. The detectors were mounted on a stereotactic biopsy table. The stereotactic technique used 2 PEM images acquired at +/-15 degrees and a new trigonometric algorithm. The accuracy and precision of the guidance method was tested by placement of small point sources of (18)F at known locations within the field of view of the imager. The calculated positions of the sources were compared with the known locations. In addition, simulated stereotactic biopsies of a breast phantom consisting of a 10-mm-diameter gelatin sphere containing a concentration of (18)F-FDG consistent with that reported for breast cancer were performed. The simulated lesion was embedded in a 4-cm-thick slab of gelatin containing a commonly reported concentration of FDG, simulating a compressed breast (target-to-background ratio, approximately 8.5:1). An anthropomorphic torso phantom was used to simulate tracer uptake in the organs of a patient 1 h after a 370-MBq injection of FDG. Five trials of the biopsy procedure were performed to assess repeatability. Finally, a method for verifying needle positioning was tested. RESULTS The positions of the point sources were successfully calculated to within 0.6 mm of their true positions with a mean error of +/-0.4 mm. The biopsy procedures, including the method for verification of needle position, were successful in all 5 trials in acquiring samples from the simulated lesions. CONCLUSION The success of this new technique shows its potential for guiding the biopsy of breast lesions optimally detected with PEM.
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Affiliation(s)
- R R Raylman
- Center for Advanced Imaging, Department of Radiology, West Virginia University, Morgantown, West Virginia 26506-9236, USA
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Abstract
BACKGROUND Venous thromboembolism (VTE) is an important complication in blunt trauma patients. At our Level I trauma center, we had a deep venous thrombosis (DVT) rate of 3.2% from 1993 to 1997 despite an aggressive VTE prophylaxis program. During this time period, we placed vena caval filters (VCF) for both traditional and prophylactic indications. This project was developed to establish a VCF registry for trauma patients to determine the long-term complications of VCF placement. METHODS A letter was sent to all trauma patients who had a VCF placed from 1993 through 1997. Patients were asked to return for a history and physical examination to detect signs and symptoms related to VTE, a duplex ultrasound of the inferior vena cava, and a plain abdominal radiograph to determine filter migration. RESULTS There were 191 VCFs inserted in our trauma population from 1993 to 1997. There were 105 patients (75 male and 30 female) available for evaluation, with a mean follow-up of 28.9 months. Forty-one VCFs were placed in patients with DVT or pulmonary embolism, and 64 were placed in patients for prophylactic indications as per the guidelines developed by the Eastern Association for the Surgery of Trauma. There were no clinically identifiable complications related to insertion of the VCF. There were no pulmonary embolisms detected after VCF insertion. In follow-up, only one filter (0.95%) migrated, and this was minimal (1 cm cephalad). One (0.95%) vena cava was occluded, based on duplex ultrasonography, and 11 patients (10.4%) had signs or symptoms of leg swelling after hospital discharge. Twenty eight (44%) of the 64 patients with prophylactic VCFs developed a DVT after filter placement. CONCLUSION VCFs placed in trauma patients have acceptable short- and long-term complication rates. Consideration should be given to prophylactic VCF placement in patients at high risk for VTE. Randomized controlled trials are needed to evaluate whether VCF insertion increases the risk for subsequent DVT.
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Affiliation(s)
- R Wojcik
- Department of Surgery, Lehigh Valley Hospital, Allentown, Pennsylvania 18105-1556, USA
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Raylman RR, Majewski S, Wojcik R, Weisenberger AG, Kross B, Popov V, Bishop HA. The potential role of positron emission mammography for detection of breast cancer. A phantom study. Med Phys 2000; 27:1943-54. [PMID: 10984240 DOI: 10.1118/1.1287439] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
Positron emission mammography (PEM) is a new, specialized imaging modality utilizing PET radiopharmaceuticals to detect breast cancer. The capabilities and limitations of PEM in detecting breast tumors were investigated with a series of phantom experiments. The PEM imager was mounted on a standard Lorad biopsy table (separated by 18 cm). In the initial phase of the investigation, basic scanner parameters (resolution, sensitivity, and scatter fraction) were measured. The effects of a number of breast imaging parameters (length of acquisition, breast thickness, and breast density) on detection of breast lesions were then explored utilizing special phantoms. Moderately compressed breasts were simulated with a block of gelatin containing amounts of FDG consistent with 370 MBq injections. Lesions were simulated with four hollow spheres (inner diameters=5 mm, 8 mm, 12 mm, and 15 mm) filled with amounts of FDG representative of uptake in malignant breast tumors (target-to-background concentration ratio=8.5:1). Resolution at the center of the imager was 3.9 mm, sensitivity was 0.059 kcps/kBq/ml and the Compton scatter fraction was approximately 12%. Objects as small as 8 mm in diameter could be detected after 30 s of data acquisition; 5 mm spheres were detectable after 300 s. Object detection capabilities were reduced with increasing breast thickness. In thin compressed breasts (2 cm) even the smallest sphere (5 mm in diameter) could be detected; increasing breast thickness increased the minimum detectable sphere diameter to 8 mm. Increased background activity caused by FDG uptake in metabolically active normal tissue more prevalent in radiodense breasts compared to "fatty" breasts was simulated and shown to reduce the minimum detectable lesion size to 12 mm for the densest breasts. These results demonstrate the potential of PEM for the detection of breast lesions. The addition of the system to a standard biopsy apparatus indicates its potential for use to guide some core biopsies of breast cancers.
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Affiliation(s)
- R R Raylman
- Department of Radiology, West Virginia University, Morgantown 26506-9236, USA.
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Abstract
In breast scintigraphy, compact detectors with high intrinsic spatial resolution and small inactive peripheries can provide improvements in extrinsic spatial resolution, efficiency and contrast for small lesions relative to larger conventional cameras. We are developing a pixelated small field-of-view gamma camera for scintimammography. Extensive measurements of the imaging properties of a prototype system have been made, including spatial resolution, sensitivity, uniformity of response, geometric linearity and energy resolution. An anthropomorphic torso phantom providing a realistic breast exit gamma spectrum has been used in a qualitative study of lesion detectability. A new type of breast imaging system that combines scintimammography and digital mammography in a single upright unit has also been developed. The system provides automatic co-registration between the scintigram and the digital mammogram, obtained with the breast in a single configuration. Intrinsic spatial resolution was evaluated via calculation of the phase-dependent modulation transfer function (MTF). Measurements of extrinsic spatial resolution, sensitivity and uniformity of response were made for two types of parallel hole collimator using NEMA (National Electrical Manufacturers Association) protocols. Geometric linearity was quantified using a line input and least squares analysis of the measured line shape. Energy resolution was measured for seven different crystal types, and the effectiveness of optical grease coupling was assessed. Exit gamma spectra were obtained using a cadmium zinc telluride based spectrometer. These were used to identify appropriate radioisotope concentrations for the various regions of an anthropomorphic torso phantom, such that realistic scatter conditions could be obtained during phantom measurements. For prone scintimammography, a special imaging table was constructed that permits simultaneous imaging of both breasts, as well as craniocaudal views. A dedicated breast imaging system was also developed that permits simultaneous acquisition and superposition of planar gamma images and digital x-ray images. The intrinsic MTF is nonstationary, and is dependent on the phase relationship between the signal and the crystal array matrix. Averaged over all phases, the MTF is approximately 0.75, 0.57 and 0.40 at spatial frequencies of 1.0, 1.5 and 2.0 cycles per cm, respectively. The phase averaged line spread function (LSF) has a FWHM value of 2.6 mm. Following uniformity corrections, the RMS deviations in flood images are only slightly greater than is predicted from counting statistics. Across an 80 mm section of the active area, the differential linearity is 0.83 mm and the absolute linearity 2.0 mm. Using an anthropomorphic torso phantom with detachable breasts, scatter radiation similar to that observed exiting the breast of scintimammography patients was observed. It was observed that scattered gamma rays can constitute the majority of the radiation incident on the detector, but that the scatter-to-primary ratio varies significantly across the field of view, being greatest in the caudal portion of the breast, where scatter from the liver is high. Using a lesion-to-breast concentration ratio of 6:1, a 1.0 cm3 simulated breast lesion was detectable in lateral images obtained with both the developmental camera and with a clinical camera, while a 0.35 cm3 lesion was detectable in neither. Utilization of the dual x-ray transmission, gamma emission breast imaging system greatly increases the conspicuity of scintimammographic lesions relative to prone imaging, as well as greatly facilitating the localization and identification of structures in the gamma image. The prototype imaging gamma detector exhibits spatial resolution superior to that of conventional cameras, and comparable uniformity of response and geometric linearity. Because of light losses in the crystals, the energy resolution is inferior to that of single crystal NaI(Tl) came
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Affiliation(s)
- M B Williams
- University of Virginia, Department of Radiology, Charlottesville 22908, USA.
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Balajewicz M, Gorecki T, Klimek R, Wojcik R. Results of computer-aided ultrasound prognosis of full fetal maturity. Int J Gynaecol Obstet 2000. [DOI: 10.1016/s0020-7292(00)82037-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Lombardo J, White C, Wojcik R. Using modern information technology to profile faculty activities. Acad Med 1998; 73:1267-1273. [PMID: 9883202 DOI: 10.1097/00001888-199812000-00016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Most academic medical centers (AMCs) have developed mechanisms for tracking the financing of their faculty members' research and clinical activities. However, information systems for managing and reporting financial data often do not provide fully accurate or complete pictures of the accomplishments of an institution or its faculty. Modern information technology can help AMCs integrate more extensive information about their faculties from many different sources; in particular, Web publishing technologies permit large numbers of users to have easy secure access to databases across different platforms. The authors briefly describe five faculty information systems now in use. They then describe in detail the development and implementation of one of these systems, The Johns Hopkins University School of Medicine Faculty Information System (FIS), which uses Web publishing technologies, collecting and making available information about the clinical, teaching, and research activities of faculty members.
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Affiliation(s)
- J Lombardo
- Faculty Information System, Johns Hopkins University Applied Physics Laboratory, Laurel, Maryland 20723-6099, USA.
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Kross B, Majewski S, Wojcik R, Zorn C, Johnson K. Preliminary results from a low dose rate irradiation of selected plastic scintillating fibers. Radiat Phys Chem Oxf Engl 1993 1993. [DOI: 10.1016/0969-806x(93)90056-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Abstract
An echocardiographic evaluation of 77 members of a championship childhood swim team showed dimensional variations from normal in most athletes. Cardiac walls were thicker than the 95th percentile of normal: right ventricular anterior wall exceeded the 95th percentile in 100%, interventricular septum in 83% and left ventricular posterior wall in 91%. The left ventricular and left atrial cavities in diastole had mean values at the 50th percentile of normal but showed considerable scatter. The left ventricular cavity in systole had a mean value less than the 5th percentile of normal and also showed wide scatter. The aortic root and the aortic intercusp dimension exceeded the 95th percentile of normal in most subjects, 74% and 77%, respectively. No correlation existed between the coach's estimate of championship ability and echocardiographic wall or chamber sizes. Children who participate extensively in athletic training programs such as swimming may have echocardiograms which are quantitatively different from those of nonathletic younsters.
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