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Nazari M, Bokhart MT, Loziuk PL, Muddiman DC. Quantitative mass spectrometry imaging of glutathione in healthy and cancerous hen ovarian tissue sections by infrared matrix-assisted laser desorption electrospray ionization (IR-MALDESI). Analyst 2018; 143:654-661. [PMID: 29323367 PMCID: PMC5788707 DOI: 10.1039/c7an01828b] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [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] [Indexed: 12/11/2022]
Abstract
A quantitative mass spectrometry imaging (QMSI) method for absolute quantification of glutathione (GSH) in healthy and cancerous hen ovarian tissues using infrared matrix-assisted laser desorption electrospray ionization (IR-MALDESI) is presented. Using this technique, the ion abundance of GSH was normalized to that of a structural analogue, which was sprayed on the slide prior to mounting the tissue sections. This normalization strategy significantly improved the voxel-to-voxel variability; the variability is attributed to the overall ionization process. Subsequently, a series of calibration spots of stable isotope-labeled (SIL) GSH were pipetted on top of the tissue to construct a spatial calibration curve, and calculate the concentration of GSH in both tissue sections. The QMSI results were verified by LC-MS/MS quantification of GSH for the same tissues. GSH was extracted from tissue sections in a slightly acidic buffer and was then alkylated using N-ethylmaleimide to minimize autoxidation of GSH to glutathione disulfide. The alkylated GSH was separated from other contaminants using reversed phase liquid chromatography (RPLC) coupled to a triple quadrupole mass spectrometer, and the z-ion transition of NEM-GSH was used to quantify GSH in each tissue section. While the absolute values obtained using IR-MALDESI QMSI and LC-MS/MS were different, a ∼2-fold increase in the concentration of GSH in cancer tissue compared to the healthy tissue was observed using both techniques. Possible reasons for the difference between absolute concentration values obtained using IR-MALDESI QMSI and LC-MS/MS are also discussed.
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Affiliation(s)
- Milad Nazari
- Department of Chemistry and Molecular Education, Technology, and Research Innovation Center (METRIC), North Carolina State University, Raleigh, NC 27695, USA.
| | - Mark T Bokhart
- Department of Chemistry and Molecular Education, Technology, and Research Innovation Center (METRIC), North Carolina State University, Raleigh, NC 27695, USA.
| | - Philip L Loziuk
- Department of Chemistry and Molecular Education, Technology, and Research Innovation Center (METRIC), North Carolina State University, Raleigh, NC 27695, USA.
| | - David C Muddiman
- Department of Chemistry and Molecular Education, Technology, and Research Innovation Center (METRIC), North Carolina State University, Raleigh, NC 27695, USA.
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Bokhart MT, Nazari M, Garrard KP, Muddiman DC. MSiReader v1.0: Evolving Open-Source Mass Spectrometry Imaging Software for Targeted and Untargeted Analyses. J Am Soc Mass Spectrom 2018; 29:8-16. [PMID: 28932998 PMCID: PMC5786496 DOI: 10.1007/s13361-017-1809-6] [Citation(s) in RCA: 156] [Impact Index Per Article: 26.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/03/2017] [Revised: 09/03/2017] [Accepted: 09/04/2017] [Indexed: 05/03/2023]
Abstract
A major update to the mass spectrometry imaging (MSI) software MSiReader is presented, offering a multitude of newly added features critical to MSI analyses. MSiReader is a free, open-source, and vendor-neutral software written in the MATLAB platform and is capable of analyzing most common MSI data formats. A standalone version of the software, which does not require a MATLAB license, is also distributed. The newly incorporated data analysis features expand the utility of MSiReader beyond simple visualization of molecular distributions. The MSiQuantification tool allows researchers to calculate absolute concentrations from quantification MSI experiments exclusively through MSiReader software, significantly reducing data analysis time. An image overlay feature allows the incorporation of complementary imaging modalities to be displayed with the MSI data. A polarity filter has also been incorporated into the data loading step, allowing the facile analysis of polarity switching experiments without the need for data parsing prior to loading the data file into MSiReader. A quality assurance feature to generate a mass measurement accuracy (MMA) heatmap for an analyte of interest has also been added to allow for the investigation of MMA across the imaging experiment. Most importantly, as new features have been added performance has not degraded, in fact it has been dramatically improved. These new tools and the improvements to the performance in MSiReader v1.0 enable the MSI community to evaluate their data in greater depth and in less time. Graphical Abstract ᅟ.
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Affiliation(s)
- Mark T Bokhart
- Department of Chemistry, W. M. Keck FTMS Laboratory for Human Health Research, Raleigh, NC, USA
| | - Milad Nazari
- Department of Chemistry, W. M. Keck FTMS Laboratory for Human Health Research, Raleigh, NC, USA
| | - Kenneth P Garrard
- Department of Chemistry, W. M. Keck FTMS Laboratory for Human Health Research, Raleigh, NC, USA
- Precision Engineering Consortium, Department of Mechanical and Aerospace Engineering, North Carolina State University, Raleigh, NC, 27695, USA
| | - David C Muddiman
- Department of Chemistry, W. M. Keck FTMS Laboratory for Human Health Research, Raleigh, NC, USA.
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Bokhart MT, Manni J, Garrard KP, Ekelöf M, Nazari M, Muddiman DC. IR-MALDESI Mass Spectrometry Imaging at 50 Micron Spatial Resolution. J Am Soc Mass Spectrom 2017; 28:2099-2107. [PMID: 28721672 PMCID: PMC5693761 DOI: 10.1007/s13361-017-1740-x] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/25/2017] [Revised: 06/15/2017] [Accepted: 06/15/2017] [Indexed: 05/04/2023]
Abstract
High spatial resolution in mass spectrometry imaging (MSI) is crucial to understanding the biology dictated by molecular distributions in complex tissue systems. Here, we present MSI using infrared matrix-assisted laser desorption electrospray ionization (IR-MALDESI) at 50 μm resolution. An adjustable iris, beam expander, and an aspherical focusing lens were used to reduce tissue ablation diameters for MSI at high resolution. The laser beam caustic was modeled using laser ablation paper to calculate relevant laser beam characteristics. The minimum laser spot diameter on the tissue was determined using tissue staining and microscopy. Finally, the newly constructed optical system was used to image hen ovarian tissue with and without oversampling, detailing tissue features at 50 μm resolution. Graphical Abstract ᅟ.
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Affiliation(s)
- Mark T Bokhart
- W.M. Keck FTMS Laboratory for Human Health Research, Department of Chemistry, North Carolina State University, Raleigh, NC, 27695, USA
| | | | - Kenneth P Garrard
- W.M. Keck FTMS Laboratory for Human Health Research, Department of Chemistry, North Carolina State University, Raleigh, NC, 27695, USA
- Precision Engineering Consortium, North Carolina State University, Raleigh, NC, 27695, USA
| | - Måns Ekelöf
- W.M. Keck FTMS Laboratory for Human Health Research, Department of Chemistry, North Carolina State University, Raleigh, NC, 27695, USA
| | - Milad Nazari
- W.M. Keck FTMS Laboratory for Human Health Research, Department of Chemistry, North Carolina State University, Raleigh, NC, 27695, USA
| | - David C Muddiman
- W.M. Keck FTMS Laboratory for Human Health Research, Department of Chemistry, North Carolina State University, Raleigh, NC, 27695, USA.
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Bokhart MT, Muddiman DC. Infrared matrix-assisted laser desorption electrospray ionization mass spectrometry imaging analysis of biospecimens. Analyst 2016; 141:5236-45. [PMID: 27484166 DOI: 10.1039/c6an01189f] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Infrared matrix-assisted laser desorption electrospray ionization (IR-MALDESI) mass spectrometry imaging (MSI) is a technique well suited for analysis of biological specimens. This tutorial review focuses on recent advancements and applications of IR-MALDESI MSI to better understand key biological questions. Through optimization of user-defined source parameters, comprehensive and quantitative MSI data can be obtained for a variety of analytes. The effect of an ice matrix layer is well defined in the context of desorption dynamics and resulting ion abundance. Optimized parameters and careful control of conditions affords quantitative MSI data which provides valuable information for targeted, label-free drug distribution studies and untargeted metabolomic datasets. Challenges and limitations of MSI using IR-MALDESI are addressed in the context of the bioimaging field.
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Affiliation(s)
- M T Bokhart
- W.M. Keck FTMS Laboratory for Human Health Research, Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695, USA.
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Nazari M, Bokhart MT, Muddiman DC. Whole-body Mass Spectrometry Imaging by Infrared Matrix-assisted Laser Desorption Electrospray Ionization (IR-MALDESI). J Vis Exp 2016:e53942. [PMID: 27077488 DOI: 10.3791/53942] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Ambient ionization sources for mass spectrometry (MS) have been the subject of much interest in the past decade. Matrix-assisted laser desorption electrospray ionization (MALDESI) is an example of such methods, where features of matrix-assisted laser desorption/ionization (MALDI) (e.g., pulsed nature of desorption) and electrospray ionization (ESI) (e.g., soft-ionization) are combined. One of the major advantages of MALDESI is its inherent versatility. In MALDESI experiments, an ultraviolet (UV) or infrared (IR) laser can be used to resonantly excite an endogenous or exogenous matrix. The choice of matrix is not analyte dependent, and depends solely on the laser wavelength used for excitation. In IR-MALDESI experiments, a thin layer of ice is deposited on the sample surface as an energy-absorbing matrix. The IR-MALDESI source geometry has been optimized using statistical design of experiments (DOE) for analysis of liquid samples as well as biological tissue specimens. Furthermore, a robust IR-MALDESI imaging source has been developed, where a tunable mid-IR laser is synchronized with a computer controlled XY translational stage and a high resolving power mass spectrometer. A custom graphical user interface (GUI) allows user selection of the repetition rate of the laser, number of shots per voxel, step-size of the sample stage, and the delay between the desorption and scan events for the source. IR-MALDESI has been used in variety of applications such as forensic analysis of fibers and dyes and MSI of biological tissue sections. Distribution of different analytes ranging from endogenous metabolites to exogenous xenobiotics within tissue sections can be measured and quantified using this technique. The protocol presented in this manuscript describes major steps necessary for IR-MALDESI MSI of whole-body tissue sections.
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Affiliation(s)
- Milad Nazari
- W. M. Keck FTMS Laboratory for Human Health Research, Department of Chemistry, North Carolina State University
| | - Mark T Bokhart
- W. M. Keck FTMS Laboratory for Human Health Research, Department of Chemistry, North Carolina State University
| | - David C Muddiman
- W. M. Keck FTMS Laboratory for Human Health Research, Department of Chemistry, North Carolina State University;
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Rosen EP, Thompson CG, Bokhart MT, Prince HMA, Sykes C, Muddiman DC, Kashuba ADM. Analysis of Antiretrovirals in Single Hair Strands for Evaluation of Drug Adherence with Infrared-Matrix-Assisted Laser Desorption Electrospray Ionization Mass Spectrometry Imaging. Anal Chem 2016; 88:1336-44. [PMID: 26688545 PMCID: PMC5301654 DOI: 10.1021/acs.analchem.5b03794] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [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: 12/19/2022]
Abstract
Adherence to a drug regimen can be a strong predictor of health outcomes, and validated measures of adherence are necessary at all stages of therapy from drug development to prescription. Many of the existing metrics of drug adherence (e.g., self-report, pill counts, blood monitoring) have limitations, and analysis of hair strands has recently emerged as an objective alternative. Traditional methods of hair analysis based on LC-MS/MS (segmenting strands at ≥1 cm length) are not capable of preserving a temporal record of drug intake at higher resolution than approximately 1 month. Here, we evaluated the detectability of HIV antiretrovirals (ARVs) in hair from a range of drug classes using infrared matrix-assisted laser desorption electrospray ionization (IR-MALDESI) mass spectrometry imaging (MSI) with 100 μm resolution. Infrared laser desorption of hair strands was shown to penetrate into the strand cortex, allowing direct measurement by MSI without analyte extraction. Using optimized desorption conditions, a linear correlation between IR-MALDESI ion abundance and LC-MS/MS response was observed for six common ARVs with estimated limits of detection less than or equal to 1.6 ng/mg hair. The distribution of efavirenz (EFV) was then monitored in a series of hair strands collected from HIV infected, virologically suppressed patients. Because of the role hair melanin plays in accumulation of basic drugs (like most ARVs), an MSI method to quantify the melanin biomarker pyrrole-2,3,5-tricarboxylic acid (PTCA) was evaluated as a means of normalizing drug response between patients to develop broadly applicable adherence criteria.
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Affiliation(s)
- Elias P. Rosen
- Eshelman School of Pharmacy, University of North Carolina, Chapel Hill, North Carolina 27599, United States
| | - Corbin G. Thompson
- Eshelman School of Pharmacy, University of North Carolina, Chapel Hill, North Carolina 27599, United States
| | - Mark T. Bokhart
- W.M. Keck FTMS Laboratory for Human Health Research, Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695, United States
| | - Heather M. A. Prince
- School of Medicine, University of North Carolina, Chapel Hill, North Carolina 27599, United States
- Center for AIDS Research, University of North Carolina, Chapel Hill, North Carolina 27599, United States
| | - Craig Sykes
- Eshelman School of Pharmacy, University of North Carolina, Chapel Hill, North Carolina 27599, United States
- Center for AIDS Research, University of North Carolina, Chapel Hill, North Carolina 27599, United States
| | - David C. Muddiman
- W.M. Keck FTMS Laboratory for Human Health Research, Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695, United States
| | - Angela D. M. Kashuba
- Eshelman School of Pharmacy, University of North Carolina, Chapel Hill, North Carolina 27599, United States
- School of Medicine, University of North Carolina, Chapel Hill, North Carolina 27599, United States
- Center for AIDS Research, University of North Carolina, Chapel Hill, North Carolina 27599, United States
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Abstract
Laser desorption followed by post electrospray ionization requires synchronized timing of the key events (sample desorption/ionization, mass spectrometry analysis, and sample translation) necessary to conduct mass spectrometry imaging (MSI) with adequate analyte sensitivity. In infrared matrix-assisted laser desorption electrospray ionization (IR-MALDESI) MSI analyses, two laser pulses are used for analysis at each volumetric element, or voxel, of a biological sample and ion accumulation in the C-trap exceeding 100 ms is necessary to capture all sample-associated ions using an infrared laser with a 20 Hz repetition rate. When coupled to an Orbitrap-based mass spectrometer like the Q Exactive Plus, this time window for ion accumulation exceeds dynamically controlled trapping of samples with comparable ion flux by Automatic Gain Control (AGC), which cannot be used during MSI analysis. In this work, a next-generation IR-MALDESI source has been designed and constructed that incorporates a mid-infrared OPO laser capable of operating at 100 Hz and allows requisite C-trap inject time during MSI to be reduced to 30 ms. Analyte detectability of the next-generation IR-MALDESI integrated source has been evaluated as a function of laser repetition rate (100-20 Hz) with corresponding C-trap ion accumulation times (30-110 ms) in both untargeted and targeted analysis of biological samples. Reducing the C-trap ion accumulation time resulted in increased ion abundance by up to 3 orders of magnitude for analytes ranging from xenobiotics to endogenous lipids, and facilitated the reduction of voxel-to-voxel variability by more than 3-fold.
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Affiliation(s)
- Elias P. Rosen
- W.M. Keck FTMS Laboratory for Human Health Research, Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695
| | - Mark T. Bokhart
- W.M. Keck FTMS Laboratory for Human Health Research, Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695
| | - Milad Nazari
- W.M. Keck FTMS Laboratory for Human Health Research, Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695
| | - David C. Muddiman
- W.M. Keck FTMS Laboratory for Human Health Research, Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695
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Rosen EP, Bokhart MT, Ghashghaei HT, Muddiman DC. Influence of Desorption Conditions on Analyte Sensitivity and Internal Energy in Discrete Tissue or Whole Body Imaging by IR-MALDESI. J Am Soc Mass Spectrom 2015; 26:899-910. [PMID: 25840812 PMCID: PMC4425634 DOI: 10.1007/s13361-015-1114-1] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [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] [Received: 12/31/2014] [Revised: 02/22/2015] [Accepted: 02/22/2015] [Indexed: 05/10/2023]
Abstract
Analyte signal in a laser desorption/postionization scheme such as infrared matrix-assisted laser desorption electrospray ionization (IR-MALDESI) is strongly coupled to the degree of overlap between the desorbed plume of neutral material from a sample and an orthogonal electrospray. In this work, we systematically examine the effect of desorption conditions on IR-MALDESI response to pharmaceutical drugs and endogenous lipids in biological tissue using a design of experiments approach. Optimized desorption conditions have then been used to conduct an untargeted lipidomic analysis of whole body sagittal sections of neonate mouse. IR-MALDESI response to a wide range of lipid classes has been demonstrated, with enhanced lipid coverage received by varying the laser wavelength used for mass spectrometry imaging (MSI). Targeted MS(2) imaging (MS(2)I) of an analyte, cocaine, deposited beneath whole body sections allowed determination of tissue-specific ion response factors, and CID fragments of cocaine were monitored to comment on wavelength-dependent internal energy deposition based on the "survival yield" method.
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Affiliation(s)
- Elias P. Rosen
- W.M. Keck FTMS Laboratory for Human Health Research, Department of Chemistry, North Carolina State University, Raleigh, North Carolina
| | - Mark T. Bokhart
- W.M. Keck FTMS Laboratory for Human Health Research, Department of Chemistry, North Carolina State University, Raleigh, North Carolina
| | - H. Troy Ghashghaei
- Department of Molecular Biomedical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, North Carolina
| | - David C. Muddiman
- W.M. Keck FTMS Laboratory for Human Health Research, Department of Chemistry, North Carolina State University, Raleigh, North Carolina
- Author for Correspondence David C. Muddiman, Ph.D., W.M. Keck FTMS Laboratory for Human Health Research, Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695, Phone: 919-513-0084,
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Barry JA, Robichaud G, Bokhart MT, Thompson C, Sykes C, Kashuba AD, Muddiman DC. Mapping antiretroviral drugs in tissue by IR-MALDESI MSI coupled to the Q Exactive and comparison with LC-MS/MS SRM assay. J Am Soc Mass Spectrom 2014; 25:2038-47. [PMID: 24744212 PMCID: PMC4201889 DOI: 10.1007/s13361-014-0884-1] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [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] [Received: 01/06/2014] [Revised: 03/05/2014] [Accepted: 03/08/2014] [Indexed: 05/09/2023]
Abstract
This work describes the coupling of the IR-MALDESI imaging source with the Q Exactive mass spectrometer. IR-MALDESI MSI was used to elucidate the spatial distribution of several HIV drugs in cervical tissues that had been incubated in either a low or high concentration. Serial sections of those analyzed by IR-MALDESI MSI were homogenized and analyzed by LC-MS/MS to quantify the amount of each drug present in the tissue. By comparing the two techniques, an agreement between the average intensities from the imaging experiment and the absolute quantities for each drug was observed. This correlation between these two techniques serves as a prerequisite to quantitative IR-MALDESI MSI. In addition, a targeted MS(2) imaging experiment was also conducted to demonstrate the capabilities of the Q Exactive and to highlight the added selectivity that can be obtained with SRM or MRM imaging experiments.
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Affiliation(s)
- Jeremy A. Barry
- W.M. Keck FT Mass Spectrometry Laboratory, Department of Chemistry, North Carolina State University, Raleigh, North Carolina
| | - Guillaume Robichaud
- W.M. Keck FT Mass Spectrometry Laboratory, Department of Chemistry, North Carolina State University, Raleigh, North Carolina
| | - Mark T. Bokhart
- W.M. Keck FT Mass Spectrometry Laboratory, Department of Chemistry, North Carolina State University, Raleigh, North Carolina
| | - Corbin Thompson
- Eshelman School of Pharmacy, The University of North Carolina, Chapel Hill, North Carolina
| | - Craig Sykes
- Eshelman School of Pharmacy, The University of North Carolina, Chapel Hill, North Carolina
| | - Angela D.M. Kashuba
- Eshelman School of Pharmacy, The University of North Carolina, Chapel Hill, North Carolina
| | - David C. Muddiman
- W.M. Keck FT Mass Spectrometry Laboratory, Department of Chemistry, North Carolina State University, Raleigh, North Carolina
- Author for Correspondence: David C. Muddiman, Ph.D., W.M. Keck FT Mass Spectrometry Laboratory, Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695, Phone: 919-513-0084, Fax: 919-513-7993,
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