1
|
Bateman NW, Tarney CM, Abulez TS, Hood BL, Conrads KA, Zhou M, Soltis AR, Teng PN, Jackson A, Tian C, Dalgard CL, Wilkerson MD, Kessler MD, Goecker Z, Loffredo J, Shriver CD, Hu H, Cote M, Parker GJ, Segars J, Al-Hendy A, Risinger JI, Phippen NT, Casablanca Y, Darcy KM, Maxwell GL, Conrads TP, O'Connor TD. Peptide ancestry informative markers in uterine neoplasms from women of European, African, and Asian ancestry. iScience 2021; 25:103665. [PMID: 35036865 PMCID: PMC8753123 DOI: 10.1016/j.isci.2021.103665] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2021] [Revised: 10/29/2021] [Accepted: 12/17/2021] [Indexed: 02/07/2023] Open
Abstract
Characterization of ancestry-linked peptide variants in disease-relevant patient tissues represents a foundational step to connect patient ancestry with disease pathogenesis. Nonsynonymous single-nucleotide polymorphisms encoding missense substitutions within tryptic peptides exhibiting high allele frequencies in European, African, and East Asian populations, termed peptide ancestry informative markers (pAIMs), were prioritized from 1000 genomes. In silico analysis identified that as few as 20 pAIMs can determine ancestry proportions similarly to >260K SNPs (R2 = 0.99). Multiplexed proteomic analysis of >100 human endometrial cancer cell lines and uterine leiomyoma tissues combined resulted in the quantitation of 62 pAIMs that correlate with patient race and genotype-confirmed ancestry. Candidates include a D451E substitution in GC vitamin D-binding protein previously associated with altered vitamin D levels in African and European populations. pAIMs will support generalized proteoancestry assessment as well as efforts investigating the impact of ancestry on the human proteome and how this relates to the pathogenesis of uterine neoplasms.
Collapse
Affiliation(s)
- Nicholas W. Bateman
- Gynecologic Cancer Center of Excellence, Department of Gynecologic Surgery and Obstetrics, Uniformed Services University and Walter Reed National Military Medical Center, 8901 Wisconsin Avenue, Bethesda, MD 20889, USA,The John P. Murtha Cancer Center, Uniformed Services University and Walter Reed National Military Medical Center, 8901 Wisconsin Avenue, Bethesda, MD 20889, USA,Henry M. Jackson Foundation for the Advancement of Military Medicine, Inc., 6720A Rockledge Dr., Suite 100, Bethesda, MD 20817, USA,Corresponding author 3289 Woodburn Rd, Suite 375, Annandale, VA 22003;
| | - Christopher M. Tarney
- Gynecologic Cancer Center of Excellence, Department of Gynecologic Surgery and Obstetrics, Uniformed Services University and Walter Reed National Military Medical Center, 8901 Wisconsin Avenue, Bethesda, MD 20889, USA
| | - Tamara S. Abulez
- Gynecologic Cancer Center of Excellence, Department of Gynecologic Surgery and Obstetrics, Uniformed Services University and Walter Reed National Military Medical Center, 8901 Wisconsin Avenue, Bethesda, MD 20889, USA,Henry M. Jackson Foundation for the Advancement of Military Medicine, Inc., 6720A Rockledge Dr., Suite 100, Bethesda, MD 20817, USA
| | - Brian L. Hood
- Gynecologic Cancer Center of Excellence, Department of Gynecologic Surgery and Obstetrics, Uniformed Services University and Walter Reed National Military Medical Center, 8901 Wisconsin Avenue, Bethesda, MD 20889, USA,Henry M. Jackson Foundation for the Advancement of Military Medicine, Inc., 6720A Rockledge Dr., Suite 100, Bethesda, MD 20817, USA
| | - Kelly A. Conrads
- Gynecologic Cancer Center of Excellence, Department of Gynecologic Surgery and Obstetrics, Uniformed Services University and Walter Reed National Military Medical Center, 8901 Wisconsin Avenue, Bethesda, MD 20889, USA,Henry M. Jackson Foundation for the Advancement of Military Medicine, Inc., 6720A Rockledge Dr., Suite 100, Bethesda, MD 20817, USA
| | - Ming Zhou
- Department of Obstetrics and Gynecology, Inova Fairfax Medical Campus, 3300 Gallows Road, Falls Church, VA 22042, USA
| | - Anthony R. Soltis
- Henry M. Jackson Foundation for the Advancement of Military Medicine, Inc., 6720A Rockledge Dr., Suite 100, Bethesda, MD 20817, USA,The American Genome Center; Uniformed Services University of the Health Sciences, Bethesda, MD 20814, USA
| | - Pang-Ning Teng
- Gynecologic Cancer Center of Excellence, Department of Gynecologic Surgery and Obstetrics, Uniformed Services University and Walter Reed National Military Medical Center, 8901 Wisconsin Avenue, Bethesda, MD 20889, USA,Henry M. Jackson Foundation for the Advancement of Military Medicine, Inc., 6720A Rockledge Dr., Suite 100, Bethesda, MD 20817, USA
| | - Amanda Jackson
- Gynecologic Cancer Center of Excellence, Department of Gynecologic Surgery and Obstetrics, Uniformed Services University and Walter Reed National Military Medical Center, 8901 Wisconsin Avenue, Bethesda, MD 20889, USA
| | - Chunqiao Tian
- Gynecologic Cancer Center of Excellence, Department of Gynecologic Surgery and Obstetrics, Uniformed Services University and Walter Reed National Military Medical Center, 8901 Wisconsin Avenue, Bethesda, MD 20889, USA,Henry M. Jackson Foundation for the Advancement of Military Medicine, Inc., 6720A Rockledge Dr., Suite 100, Bethesda, MD 20817, USA
| | - Clifton L. Dalgard
- The American Genome Center; Uniformed Services University of the Health Sciences, Bethesda, MD 20814, USA,Department of Anatomy Physiology and Genetics, Uniformed Services University, 4301 Jones Bridge Road, Bethesda, MD 20814, USA
| | - Matthew D. Wilkerson
- The John P. Murtha Cancer Center, Uniformed Services University and Walter Reed National Military Medical Center, 8901 Wisconsin Avenue, Bethesda, MD 20889, USA,Henry M. Jackson Foundation for the Advancement of Military Medicine, Inc., 6720A Rockledge Dr., Suite 100, Bethesda, MD 20817, USA,The American Genome Center; Uniformed Services University of the Health Sciences, Bethesda, MD 20814, USA,Department of Anatomy Physiology and Genetics, Uniformed Services University, 4301 Jones Bridge Road, Bethesda, MD 20814, USA
| | - Michael D. Kessler
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Zachary Goecker
- University of California, Davis, One Shields Avenue, Davis, CA 95616, USA
| | - Jeremy Loffredo
- Gynecologic Cancer Center of Excellence, Department of Gynecologic Surgery and Obstetrics, Uniformed Services University and Walter Reed National Military Medical Center, 8901 Wisconsin Avenue, Bethesda, MD 20889, USA
| | - Craig D. Shriver
- The John P. Murtha Cancer Center, Uniformed Services University and Walter Reed National Military Medical Center, 8901 Wisconsin Avenue, Bethesda, MD 20889, USA
| | - Hai Hu
- The John P. Murtha Cancer Center, Uniformed Services University and Walter Reed National Military Medical Center, 8901 Wisconsin Avenue, Bethesda, MD 20889, USA,Chan Soon-Shiong Institute of Molecular Medicine at Windber, Windber, PA 15963, USA
| | | | - Glendon J. Parker
- University of California, Davis, One Shields Avenue, Davis, CA 95616, USA
| | - James Segars
- Johns Hopkins University Medical Center, Baltimore, MD 21218, USA
| | - Ayman Al-Hendy
- The University of Illinois College of Medicine, Chicago, IL 60612, USA
| | - John I. Risinger
- Department of Obstetrics and Gynecology, Michigan State University, East Lansing, MI 48824, USA
| | - Neil T. Phippen
- Gynecologic Cancer Center of Excellence, Department of Gynecologic Surgery and Obstetrics, Uniformed Services University and Walter Reed National Military Medical Center, 8901 Wisconsin Avenue, Bethesda, MD 20889, USA,The John P. Murtha Cancer Center, Uniformed Services University and Walter Reed National Military Medical Center, 8901 Wisconsin Avenue, Bethesda, MD 20889, USA
| | - Yovanni Casablanca
- Gynecologic Cancer Center of Excellence, Department of Gynecologic Surgery and Obstetrics, Uniformed Services University and Walter Reed National Military Medical Center, 8901 Wisconsin Avenue, Bethesda, MD 20889, USA,The John P. Murtha Cancer Center, Uniformed Services University and Walter Reed National Military Medical Center, 8901 Wisconsin Avenue, Bethesda, MD 20889, USA
| | - Kathleen M. Darcy
- Gynecologic Cancer Center of Excellence, Department of Gynecologic Surgery and Obstetrics, Uniformed Services University and Walter Reed National Military Medical Center, 8901 Wisconsin Avenue, Bethesda, MD 20889, USA,The John P. Murtha Cancer Center, Uniformed Services University and Walter Reed National Military Medical Center, 8901 Wisconsin Avenue, Bethesda, MD 20889, USA,Henry M. Jackson Foundation for the Advancement of Military Medicine, Inc., 6720A Rockledge Dr., Suite 100, Bethesda, MD 20817, USA
| | - G. Larry Maxwell
- Gynecologic Cancer Center of Excellence, Department of Gynecologic Surgery and Obstetrics, Uniformed Services University and Walter Reed National Military Medical Center, 8901 Wisconsin Avenue, Bethesda, MD 20889, USA,The John P. Murtha Cancer Center, Uniformed Services University and Walter Reed National Military Medical Center, 8901 Wisconsin Avenue, Bethesda, MD 20889, USA,Department of Obstetrics and Gynecology, Inova Fairfax Medical Campus, 3300 Gallows Road, Falls Church, VA 22042, USA
| | - Thomas P. Conrads
- Gynecologic Cancer Center of Excellence, Department of Gynecologic Surgery and Obstetrics, Uniformed Services University and Walter Reed National Military Medical Center, 8901 Wisconsin Avenue, Bethesda, MD 20889, USA,The John P. Murtha Cancer Center, Uniformed Services University and Walter Reed National Military Medical Center, 8901 Wisconsin Avenue, Bethesda, MD 20889, USA,Department of Obstetrics and Gynecology, Inova Fairfax Medical Campus, 3300 Gallows Road, Falls Church, VA 22042, USA
| | - Timothy D. O'Connor
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, MD 21201, USA,Program in Personalize and Genomic Medicine, University of Maryland School of Medicine, Baltimore, MD 21201, USA,Marlene and Stewart Greenebaum Comprehensive Cancer, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| |
Collapse
|
2
|
Goecker ZC, Legg KM, Salemi MR, Herren AW, Phinney BS, McKiernan HE, Parker GJ. Alternative LC-MS/MS Platforms and Data Acquisition Strategies for Proteomic Genotyping of Human Hair Shafts. J Proteome Res 2021; 20:4655-4666. [PMID: 34491751 DOI: 10.1021/acs.jproteome.1c00209] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Protein is a major component of all biological evidence. Proteomic genotyping is the use of genetically variant peptides (GVPs) that contain single-amino-acid polymorphisms to infer the genotype of matching nonsynonymous single-nucleotide polymorphisms for the individual from whom the protein sample originated. This can be used to statistically associate an individual to evidence found at a crime scene. The utility of the inferred genotype increases as the detection of GVPs increases, which is the direct result of technology transfer to mass spectrometry platforms typically available. Digests of single (2 cm) human hair shafts from three European and two African subjects were analyzed using data-dependent acquisition on a Q-Exactive Plus Hybrid Quadrupole-Orbitrap system, data-independent acquisition and a variant of parallel reaction monitoring (PRM) on an Orbitrap Fusion Lumos Tribrid system, and multiple reaction monitoring (MRM) on an Agilent 6495 triple quadrupole system. In our hands, average GVP detection from a selected panel of 24 GVPs increased from 6.5 ± 1.1 and 3.1 ± 0.8 using data-dependent and -independent acquisition to 9.5 ± 0.7 and 11.7 ± 1.7 using PRM and MRM (p < 0.05), respectively. PRM resulted in a 1.3-fold increase in detection sensitivity, and MRM resulted in a 1.6-fold increase in detection sensitivity. This increase in biomarker detection has a functional impact on the statistical association of a protein sample and an individual. Increased biomarker sensitivity, using Markov Chain Monte Carlo modeling, produced a median-estimated random match probability of over 1 in 10 trillion from a single hair using targeted proteomics. For PRM and MRM, detected GVPs were validated by the inclusion of stable isotope-labeled peptides in each sample, which served also as a detection trigger. This research accomplishes two aims: the demonstration of utility for alternative analytical platforms in proteomic genotyping and the establishment of validation methods for the evaluation of inferred genotypes.
Collapse
Affiliation(s)
- Zachary C Goecker
- Department of Environmental Toxicology, University of California, Davis, California 95616, United States
| | - Kevin M Legg
- The Center for Forensic Science Research and Education, Willow Grove, Pennsylvania 19090, United States
| | - Michelle R Salemi
- Proteomics Core Facility, University of California, Davis, California 95616, United States
| | - Anthony W Herren
- Proteomics Core Facility, University of California, Davis, California 95616, United States
| | - Brett S Phinney
- Proteomics Core Facility, University of California, Davis, California 95616, United States
| | - Heather E McKiernan
- The Center for Forensic Science Research and Education, Willow Grove, Pennsylvania 19090, United States
| | - Glendon J Parker
- Department of Environmental Toxicology, University of California, Davis, California 95616, United States
| |
Collapse
|
3
|
Karim N, Plott TJ, Durbin-Johnson BP, Rocke DM, Salemi M, Phinney BS, Goecker ZC, Pieterse MJM, Parker GJ, Rice RH. Elucidation of familial relationships using hair shaft proteomics. Forensic Sci Int Genet 2021; 54:102564. [PMID: 34315035 DOI: 10.1016/j.fsigen.2021.102564] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [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: 01/15/2021] [Revised: 07/08/2021] [Accepted: 07/14/2021] [Indexed: 01/01/2023]
Abstract
This study examines the potential of hair shaft proteomic analysis to delineate genetic relatedness. Proteomic profiling and amino acid sequence analysis provide information for quantitative and statistically-based analysis of individualization and sample similarity. Protein expression levels are a function of cell-specific transcriptional and translational programs. These programs are greatly influenced by an individual's genetic background, and are therefore influenced by familial relatedness as well as ancestry and genetic disease. Proteomic profiles should therefore be more similar among related individuals than unrelated individuals. Likewise, profiles of genetically variant peptides that contain single amino acid polymorphisms, the result of non-synonymous SNP alleles, should behave similarly. The proteomically-inferred SNP alleles should also provide a basis for calculation of combined paternity and sibship indices. We test these hypotheses using matching proteomic and genetic datasets from a family of two adults and four siblings, one of which has a genetic condition that perturbs hair structure and properties. We demonstrate that related individuals, compared to those who are unrelated, have more similar proteomic profiles, profiles of genetically variant peptides and higher combined paternity indices and combined sibship indices. This study builds on previous analyses of hair shaft protein profiling and genetically variant peptide profiles in different real-world scenarios including different human hair shaft body locations and pigmentation status. It also validates the inclusion of proteomic information with other biomolecular substrates in forensic hair shaft analysis, including mitochondrial and nuclear DNA.
Collapse
Affiliation(s)
- Noreen Karim
- Department of Environmental Toxicology, University of California, Davis, USA
| | - Tempest J Plott
- Department of Environmental Toxicology, University of California, Davis, USA; Forensic Science Program, University of California, Davis, USA
| | - Blythe P Durbin-Johnson
- Division of Biostatistics, Department of Public Health Sciences, Clinical and Translational, Science Center Biostatistics Core, University of California, Davis, USA
| | - David M Rocke
- Division of Biostatistics, Department of Public Health Sciences, Clinical and Translational, Science Center Biostatistics Core, University of California, Davis, USA
| | - Michelle Salemi
- Proteomics Core Facility, University of California, Davis, USA
| | - Brett S Phinney
- Proteomics Core Facility, University of California, Davis, USA
| | - Zachary C Goecker
- Department of Environmental Toxicology, University of California, Davis, USA
| | - Marc J M Pieterse
- Department of Environmental Toxicology, University of California, Davis, USA
| | - Glendon J Parker
- Department of Environmental Toxicology, University of California, Davis, USA; Forensic Science Program, University of California, Davis, USA
| | - Robert H Rice
- Department of Environmental Toxicology, University of California, Davis, USA; Forensic Science Program, University of California, Davis, USA
| |
Collapse
|
4
|
Goecker ZC, Salemi MR, Karim N, Phinney BS, Rice RH, Parker GJ. Optimal processing for proteomic genotyping of single human hairs. Forensic Sci Int Genet 2020; 47:102314. [DOI: 10.1016/j.fsigen.2020.102314] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2019] [Revised: 03/25/2020] [Accepted: 05/15/2020] [Indexed: 01/08/2023]
|
5
|
Franklin RN, Karim N, Goecker ZC, Durbin-Johnson BP, Rice RH, Parker GJ. Proteomic genotyping: Using mass spectrometry to infer SNP genotypes in pigmented and non-pigmented hair. Forensic Sci Int 2020; 310:110200. [DOI: 10.1016/j.forsciint.2020.110200] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2019] [Revised: 01/23/2020] [Accepted: 02/13/2020] [Indexed: 12/26/2022]
|
6
|
Catlin LA, Chou RM, Goecker ZC, Mullins LA, Silva DSBSS, Spurbeck RR, Parker GJ, Bartling CM. Demonstration of a mitochondrial DNA-compatible workflow for genetically variant peptide identification from human hair samples. Forensic Sci Int Genet 2019; 43:102148. [DOI: 10.1016/j.fsigen.2019.102148] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2019] [Revised: 07/29/2019] [Accepted: 08/14/2019] [Indexed: 12/01/2022]
|
7
|
Sterling S, Mason KE, Anex DS, Parker GJ, Hart B, Prinz M. Combined
DNA
Typing and Protein Identification from Unfired Brass Cartridges,,,. J Forensic Sci 2019; 64:1475-1481. [DOI: 10.1111/1556-4029.14042] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2018] [Revised: 02/15/2019] [Accepted: 02/15/2019] [Indexed: 12/25/2022]
Affiliation(s)
| | - Katelyn E. Mason
- Lawrence Livermore National Laboratory 7000 East Avenue Livermore CA 94550
| | - Deon S. Anex
- Lawrence Livermore National Laboratory 7000 East Avenue Livermore CA 94550
| | | | - Bradley Hart
- Lawrence Livermore National Laboratory 7000 East Avenue Livermore CA 94550
| | - Mechthild Prinz
- John Jay College of Criminal Justice 524 W. 59th St. New York NY 10019
| |
Collapse
|
8
|
Wu PW, Mason KE, Durbin-Johnson BP, Salemi M, Phinney BS, Rocke DM, Parker GJ, Rice RH. Proteomic analysis of hair shafts from monozygotic twins: Expression profiles and genetically variant peptides. Proteomics 2017; 17. [PMID: 28544375 DOI: 10.1002/pmic.201600462] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [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: 11/25/2016] [Revised: 05/03/2017] [Accepted: 05/16/2017] [Indexed: 11/10/2022]
Abstract
Forensic association of hair shaft evidence with individuals is currently assessed by comparing mitochondrial DNA haplotypes of reference and casework samples, primarily for exclusionary purposes. Present work tests and validates more recent proteomic approaches to extract quantitative transcriptional and genetic information from hair samples of monozygotic twin pairs, which would be predicted to partition away from unrelated individuals if the datasets contain identifying information. Protein expression profiles and polymorphic, genetically variant hair peptides were generated from ten pairs of monozygotic twins. Profiling using the protein tryptic digests revealed that samples from identical twins had typically an order of magnitude fewer protein expression differences than unrelated individuals. The data did not indicate that the degree of difference within twin pairs increased with age. In parallel, data from the digests were used to detect genetically variant peptides that result from common nonsynonymous single nucleotide polymorphisms in genes expressed in the hair follicle. Compilation of the variants permitted sorting of the samples by hierarchical clustering, permitting accurate matching of twin pairs. The results demonstrate that genetic differences are detectable by proteomic methods and provide a framework for developing quantitative statistical estimates of personal identification that increase the value of hair shaft evidence.
Collapse
Affiliation(s)
- Pei-Wen Wu
- Forensic Science Graduate Program and Department of Environmental Toxicology, University of California, Davis, CA, USA
| | - Katelyn E Mason
- Forensic Science Center, Lawrence Livermore National Laboratory, Livermore, CA, USA
| | - Blythe P Durbin-Johnson
- Division of Biostatistics, Department of Public Health Sciences, Clinical and Translational Science Center Biostatistics Core, University of California, Davis, CA, USA
| | - Michelle Salemi
- Proteomics Core Facility, University of California, Davis, CA, USA
| | - Brett S Phinney
- Proteomics Core Facility, University of California, Davis, CA, USA
| | - David M Rocke
- Division of Biostatistics, Department of Public Health Sciences, Clinical and Translational Science Center Biostatistics Core, University of California, Davis, CA, USA
| | - Glendon J Parker
- Forensic Science Center, Lawrence Livermore National Laboratory, Livermore, CA, USA.,Protein-Based Identification Technologies, Orem, UT, USA
| | - Robert H Rice
- Forensic Science Graduate Program and Department of Environmental Toxicology, University of California, Davis, CA, USA
| |
Collapse
|
9
|
Davies GR, Hadjiprocopis A, Altmann DR, Chard DT, Griffin CM, Rashid W, Parker GJ, Tofts PS, Kapoor R, Thompson AJ, Miller DH. Normal-appearing grey and white matter T1 abnormality in early relapsing–remitting multiple sclerosis: a longitudinal study. Mult Scler 2017; 13:169-77. [PMID: 17439881 DOI: 10.1177/1352458506070726] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [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: 11/17/2022]
Abstract
Objective To investigate the presence and evolution of T1 relaxation time abnormalities in normal-appearing white matter (NAWM) and grey matter (GM), early in the course of relapsing–remitting multiple sclerosis (MS). Methods Twenty-three patients with early relapsing–remitting MS and 14 healthy controls were imaged six monthly for up to three years. Mean follow-up was 26 months for MS patients and 24 months for controls. Dual-echo fast-spin echo and gradient-echo proton-density and T1-weighted data sets (permitting the calculation of a T1 map) were acquired in all subjects. GM and NAWM T1 histograms were produced and a hierarchical regression model was used to investigate changes in T1 over time. Results At baseline, significant patient-control differences were seen, both in NAWM (P = 0.001) and in GM (P = 0.01). At follow-up, there was no evidence for a serial change in either mean T1 or peak-location for either NAWM or GM. There was weak evidence for a decline in patient NAWM peak-height and also evidence for a decline in control GM peak-height. Conclusion There are significant and persistent abnormalities of NAWM and GM T1 in early relapsing-remitting MS. Further studies should address whether such T1 measures have a role in prognosis or therapeutic monitoring. Multiple Sclerosis 2007; 13:169–177. http://msj.sagepub.com
Collapse
Affiliation(s)
- G R Davies
- NMR Research Unit, Institute of Neurology, University College London, Queen Square, London, UK
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
10
|
Parker GJ, Leppert T, Anex DS, Hilmer JK, Matsunami N, Baird L, Stevens J, Parsawar K, Durbin-Johnson BP, Rocke DM, Nelson C, Fairbanks DJ, Wilson AS, Rice RH, Woodward SR, Bothner B, Hart BR, Leppert M. Demonstration of Protein-Based Human Identification Using the Hair Shaft Proteome. PLoS One 2016; 11:e0160653. [PMID: 27603779 PMCID: PMC5014411 DOI: 10.1371/journal.pone.0160653] [Citation(s) in RCA: 70] [Impact Index Per Article: 8.8] [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: 09/24/2015] [Accepted: 07/21/2016] [Indexed: 12/28/2022] Open
Abstract
Human identification from biological material is largely dependent on the ability to characterize genetic polymorphisms in DNA. Unfortunately, DNA can degrade in the environment, sometimes below the level at which it can be amplified by PCR. Protein however is chemically more robust than DNA and can persist for longer periods. Protein also contains genetic variation in the form of single amino acid polymorphisms. These can be used to infer the status of non-synonymous single nucleotide polymorphism alleles. To demonstrate this, we used mass spectrometry-based shotgun proteomics to characterize hair shaft proteins in 66 European-American subjects. A total of 596 single nucleotide polymorphism alleles were correctly imputed in 32 loci from 22 genes of subjects' DNA and directly validated using Sanger sequencing. Estimates of the probability of resulting individual non-synonymous single nucleotide polymorphism allelic profiles in the European population, using the product rule, resulted in a maximum power of discrimination of 1 in 12,500. Imputed non-synonymous single nucleotide polymorphism profiles from European-American subjects were considerably less frequent in the African population (maximum likelihood ratio = 11,000). The converse was true for hair shafts collected from an additional 10 subjects with African ancestry, where some profiles were more frequent in the African population. Genetically variant peptides were also identified in hair shaft datasets from six archaeological skeletal remains (up to 260 years old). This study demonstrates that quantifiable measures of identity discrimination and biogeographic background can be obtained from detecting genetically variant peptides in hair shaft protein, including hair from bioarchaeological contexts.
Collapse
Affiliation(s)
- Glendon J. Parker
- Department of Biology, Utah Valley University, Orem, Utah, United States of America
- Protein-Based Identification Technologies L.L.C., Orem, Utah, United States of America
- * E-mail: parker64@llnl;
| | - Tami Leppert
- Protein-Based Identification Technologies L.L.C., Orem, Utah, United States of America
- Department of Human Genetics, University of Utah, Salt Lake City, Utah, United States of America
| | - Deon S. Anex
- Forensic Science Center, Lawrence Livermore National Laboratory, Livermore, California, United States of America
| | - Jonathan K. Hilmer
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, Montana, United States of America
| | - Nori Matsunami
- Department of Human Genetics, University of Utah, Salt Lake City, Utah, United States of America
| | - Lisa Baird
- Department of Human Genetics, University of Utah, Salt Lake City, Utah, United States of America
| | - Jeffery Stevens
- Department of Human Genetics, University of Utah, Salt Lake City, Utah, United States of America
| | - Krishna Parsawar
- Mass Spectrometry and Proteomics Core Facility, University of Utah, Salt Lake City, Utah, United States of America
| | - Blythe P. Durbin-Johnson
- Department of Public Health Sciences, University of California, Davis, California, United States of America
| | - David M. Rocke
- Department of Public Health Sciences, University of California, Davis, California, United States of America
| | - Chad Nelson
- Mass Spectrometry and Proteomics Core Facility, University of Utah, Salt Lake City, Utah, United States of America
| | - Daniel J. Fairbanks
- Department of Biology, Utah Valley University, Orem, Utah, United States of America
| | - Andrew S. Wilson
- School of Archaeological Sciences, University of Bradford, Bradford, United Kingdom
| | - Robert H. Rice
- Department of Environmental Toxicology, University of California, Davis, California, United States of America
| | - Scott R. Woodward
- Sorenson Molecular Genealogical Foundation, Salt Lake City, Utah, United States of America
| | - Brian Bothner
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, Montana, United States of America
| | - Bradley R. Hart
- Forensic Science Center, Lawrence Livermore National Laboratory, Livermore, California, United States of America
| | - Mark Leppert
- Department of Human Genetics, University of Utah, Salt Lake City, Utah, United States of America
| |
Collapse
|
11
|
Fairbanks DJ, Fairbanks AD, Ogden TH, Parker GJ, Maughan PJ. NANOGP8: evolution of a human-specific retro-oncogene. G3 (Bethesda) 2012; 2:1447-57. [PMID: 23173096 PMCID: PMC3484675 DOI: 10.1534/g3.112.004366] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/25/2012] [Accepted: 09/18/2012] [Indexed: 12/22/2022]
Abstract
NANOGP8 is a human (Homo sapiens) retrogene, expressed predominantly in cancer cells where its protein product is tumorigenic. It arose through retrotransposition from its parent gene, NANOG, which is expressed predominantly in embryonic stem cells. Based on identification of fixed and polymorphic variants in a genetically diverse set of human NANOG and NANOGP8 sequences, we estimated the evolutionary origin of NANOGP8 at approximately 0.9 to 2.5 million years ago, more recent than previously estimated. We also discovered that NANOGP8 arose from a derived variant allele of NANOG containing a 22-nucleotide pair deletion in the 3' UTR, which has remained polymorphic in modern humans. Evidence from our experiments indicates that NANOGP8 is fixed in modern humans even though its parent allele is polymorphic. The presence of NANOGP8-specific sequences in Neanderthal reads provided definitive evidence that NANOGP8 is also present in the Neanderthal genome. Some variants between the reference sequences of NANOG and NANOGP8 utilized in cancer research to distinguish RT-PCR products are polymorphic within NANOG or NANOGP8 and thus are not universally reliable as distinguishing features. NANOGP8 was inserted in reverse orientation into the LTR region of an SVA retroelement that arose in a human-chimpanzee-gorilla common ancestor after divergence of the orangutan ancestral lineage. Transcription factor binding sites within and beyond this LTR may promote expression of NANOGP8 in cancer cells, although current evidence is inferential. The fact that NANOGP8 is a human-specific retro-oncogene may partially explain the higher genetic predisposition for cancer in humans compared with other primates.
Collapse
Affiliation(s)
- Daniel J. Fairbanks
- Department of Biology, Utah Valley University, Orem, Utah 84058
- Department of Plant and Wildlife Sciences, Brigham Young University, Provo, Utah 84602
| | | | - T. Heath Ogden
- Department of Biology, Utah Valley University, Orem, Utah 84058
| | | | - Peter J. Maughan
- Department of Plant and Wildlife Sciences, Brigham Young University, Provo, Utah 84602
| |
Collapse
|
12
|
Ryu JH, Drain J, Kim JH, McGee S, Gray-Weale A, Waddington L, Parker GJ, Hargreaves M, Yoo SH, Stapleton D. Comparative structural analyses of purified glycogen particles from rat liver, human skeletal muscle and commercial preparations. Int J Biol Macromol 2009; 45:478-82. [DOI: 10.1016/j.ijbiomac.2009.08.006] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2009] [Revised: 08/19/2009] [Accepted: 08/20/2009] [Indexed: 10/20/2022]
|
13
|
Parker GJ. Glycogen Protects Clear‐Cell Carcinoma: dependence on the hypoxia inducible pathway and a potential therapeutic role for glycogenolysis inhibitors. FASEB J 2009. [DOI: 10.1096/fasebj.23.1_supplement.678.10] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
|
14
|
Taylor RP, Parker GJ, Hazel MW, Soesanto Y, Fuller W, Yazzie MJ, McClain DA. Glucose deprivation stimulates O-GlcNAc modification of proteins through up-regulation of O-linked N-acetylglucosaminyltransferase. J Biol Chem 2008; 283:6050-7. [PMID: 18174169 DOI: 10.1074/jbc.m707328200] [Citation(s) in RCA: 115] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
O-Linked N-acetylglucosamine (O-GlcNAc) is a post-translational modification of proteins that functions as a nutrient sensing mechanism. Here we report on regulation of O-GlcNAcylation over a broad range of glucose concentrations. We have discovered a significant induction of O-GlcNAc modification of a limited number of proteins under conditions of glucose deprivation. Beginning 12 h after treatment, glucose-deprived human hepatocellular carcinoma (HepG2) cells demonstrate a 7.8-fold increase in total O-GlcNAc modification compared with cells cultured in normal glucose (5 mm; p = 0.008). Some of the targets of glucose deprivation-induced O-GlcNAcylation are distinct from those modified in response to high glucose (20 mm) or glucosamine (10 mm) treatment, suggesting differential targeting with glucose deprivation and glucose excess. O-GlcNAcylation of glycogen synthase is significantly increased with glucose deprivation, and this O-GlcNAc increase contributes to a 60% decrease (p = 0.004) in glycogen synthase activity. Increased O-GlcNAc modification is not mediated by increased UDP-GlcNAc, the rate-limiting substrate for O-GlcNAcylation. Rather, the mRNA for nucleocytoplasmic O-linked N-acetylglucosaminyltransferase (OGT) increases 3.4-fold within 6 h of glucose deprivation (p = 0.006). Within 12 h, OGT protein increases 1.7-fold (p = 0.01) compared with normal glucose-treated cells. In addition, 12-h glucose deprivation leads to a 49% decrease in O-GlcNAcase protein levels (p = 0.03). We conclude that increased O-GlcNAc modification stimulated by glucose deprivation results from increased OGT and decreased O-GlcNAcase levels and that these changes affect cell metabolism, thus inactivating glycogen synthase.
Collapse
Affiliation(s)
- Rodrick P Taylor
- Departments of Biochemistry and Medicine, University of Utah School of Medicine, 30 N. 2030 East, Salt Lake City, UT 84132, USA
| | | | | | | | | | | | | |
Collapse
|
15
|
Wende AR, Schaeffer PJ, Parker GJ, Zechner C, Han DH, Chen MM, Hancock CR, Lehman JJ, Huss JM, McClain DA, Holloszy JO, Kelly DP. A Role for the Transcriptional Coactivator PGC-1α in Muscle Refueling. J Biol Chem 2007; 282:36642-51. [DOI: 10.1074/jbc.m707006200] [Citation(s) in RCA: 204] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
|
16
|
Parker GJ, Koay A, Gilbert-Wilson R, Waddington LJ, Stapleton D. AMP-activated protein kinase does not associate with glycogen alpha-particles from rat liver. Biochem Biophys Res Commun 2007; 362:811-5. [PMID: 17767922 DOI: 10.1016/j.bbrc.2007.08.080] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2007] [Accepted: 08/07/2007] [Indexed: 11/28/2022]
Abstract
The AMP-activated protein kinase (AMPK) is heterotrimer consisting of alpha catalytic subunit and beta/gamma regulatory subunits. It acts as a critical focal point for whole body and cellular mechanisms maintaining energy homeostasis by regulating carbohydrate and lipid metabolism, food intake, gene transcription, and protein synthesis. The AMPK beta subunit contains a glycogen-binding domain that has been shown to associate with glycogen particles in vitro and glycogen phosphorylase and glycogen synthase in cultured cells. To determine whether AMPK associates with glycogen particles in vivo, we developed a procedure to purify glycogen alpha-particles to apparent homogeneity from rat liver. Using immunoreactivity and mass spectrometry we determined that AMPK does not associate with the glycogen particle in livers from random-fed rats. This surprising finding indicates that the glycogen-binding properties of the AMPK beta subunit are likely regulated and responsive to the metabolic status of the hepatocyte.
Collapse
Affiliation(s)
- Glendon J Parker
- Department of Medicine, Rm 4C464B SOM, 30 N 1900 E, 84132, School of Medicine, University of Utah, Salt Lake City, UT, USA
| | | | | | | | | |
Collapse
|
17
|
Affiliation(s)
- Glendon J Parker
- MedicineUniversity of Utah4C464B SOM, 30 N 1900 ESalt Lake CityUT84132
| | - Chad Nelson
- University of Utah20 South 2030 East, Room 470 BPRBSalt Lake CityUT84132
| | - Krishna Parsawar
- University of Utah20 South 2030 East, Room 470 BPRBSalt Lake CityUT84132
| | - David Stapleton
- University of Melbourne30 Flemington Road, Parkville, MelbourneVictoria3010Australia
| | | |
Collapse
|
18
|
Luo B, Parker GJ, Cooksey RC, Soesanto Y, Evans M, Jones D, McClain DA. Chronic hexosamine flux stimulates fatty acid oxidation by activating AMP-activated protein kinase in adipocytes. J Biol Chem 2007; 282:7172-80. [PMID: 17227772 DOI: 10.1074/jbc.m607362200] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The hexosamine biosynthesis pathway (HBP) serves as a nutrient sensor and has been implicated in the development of type 2 diabetes. We previously demonstrated that fatty acid oxidation was enhanced in transgenic mouse adipocytes, wherein the rate-limiting enzyme of the HBP, glutamine:fructose-6-phosphate amidotransferase (GFA), was overexpressed. To explore the molecular mechanism of the HBP-induced fatty acid oxidation in adipocytes, we studied AMP-activated protein kinase (AMPK), an energy sensor that stimulates fatty acid oxidation by regulating acetyl-CoA carboxylase (ACC) activity. Phosphorylation and activity of AMPK were increased in transgenic fat pads and in 3T3L1 adipocytes treated with glucosamine to stimulate hexosamine flux. Glucosamine also stimulated phosphorylation of ACC and fatty acid oxidation in 3T3L1 adipocytes, and these stimulatory effects were diminished by adenovirus-mediated expression of a dominant negative AMPK in 3T3L1 adipocytes. Conversely, blocking the HBP with a GFA inhibitor reduced AMPK activity, ACC phosphorylation, and fatty acid oxidation. These changes are not explained by alterations in the cellular AMP/ATP ratio. Further demonstrating that AMPK is regulated by the HBP, we found that AMPK was recognized by succinylated wheat germ agglutinin, which specifically binds O-GlcNAc. The levels of AMPK in succinylated wheat germ agglutinin precipitates correlated with hexosamine flux in mouse fat pads and 3T3L1 adipocytes. Moreover, removal of O-GlcNAc by hexosaminidase reduced AMPK activity. We conclude that chronically high hexosamine flux stimulates fatty acid oxidation by activating AMPK in adipocytes, in part through O-linked glycosylation.
Collapse
Affiliation(s)
- Bai Luo
- Division of Endocrinology, University of Utah School of Medicine and Veterans Affairs Medical Center, Salt Lake City, Utah 84132, USA
| | | | | | | | | | | | | |
Collapse
|
19
|
Parker GJ, Charlton MDB, Zoorob ME, Baumberg JJ, Netti MC, Lee T. Highly engineered mesoporous structures for optical processing. Philos Trans A Math Phys Eng Sci 2006; 364:189-199. [PMID: 18272460 DOI: 10.1098/rsta.2005.1693] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Arranging periodic, or quasi-periodic, regions of differing refractive index in one, two, or three dimensions can form a unique class of mesoporous structures. These structures are generally known as photonic crystals, or photonic quasicrystals, and they are the optical analogue of semiconducting materials. Whereas a semiconductor's band structure arises from the interaction of electron or hole waves with an arrangement of ion cores, the photonic crystal band structure results from the interaction of light waves with an arrangement of regions of differing refractive index. What makes photonic crystals highly attractive to the optical engineer is that we can actually place the regions of differing refractive index in a pattern specifically tailored to produce a given optical function, such as an extremely high dispersion, for example. That is, we can define the geometrical arrangement of the dielectric foam to provide us with the form of band structure we require for our optical functionality. In this paper, the optical properties and applications of these highly engineered mesoporous dielectrics will be discussed.
Collapse
Affiliation(s)
- G J Parker
- School of Electronics and Computer Science, The University of Southampton, Southampton SO17 1BJ, UK.
| | | | | | | | | | | |
Collapse
|
20
|
Finlayson CE, Cattaneo F, Perney NMB, Baumberg JJ, Netti MC, Zoorob ME, Charlton MDB, Parker GJ. Slow light and chromatic temporal dispersion in photonic crystal waveguides using femtosecond time of flight. Phys Rev E Stat Nonlin Soft Matter Phys 2006; 73:016619. [PMID: 16486307 DOI: 10.1103/physreve.73.016619] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/21/2005] [Indexed: 05/06/2023]
Abstract
We report time-of-flight experiments on photonic-crystal waveguide structures using optical Kerr gating of a femtosecond white-light supercontinuum. These photonic-crystal structures, based on engineered silicon-nitride slab waveguides, possess broadband low-loss guiding properties, allowing the group velocity dispersion of optical pulses to be directly tracked as a function of wavelength. This dispersion is shown to be radically disrupted by the spectral band gaps associated with the photonic-crystal periodicity. Increased time-of-flight effects, or "slowed light," are clearly observed at the edges of band gaps in agreement with two-dimensional plane-wave theoretical models of group velocity dispersion. A universal model for slow light in such photonic crystals is proposed, which shows that slow light is controlled predominantly by the detuning from, and the size of, the photonic band gaps. Slowed light observed up to time delays of approximately 1 ps, corresponds to anomalous dispersion of approximately 3.5 ps/nm per mm of the photonic crystal structure. From the decreasing intensity of time-gated slow light as a function of time delay, we estimate the characteristic losses of modes which are guided in the spectral proximity of the photonic band gaps.
Collapse
Affiliation(s)
- C E Finlayson
- School of Physics & Astronomy, University of Southampton, Southampton SO17 1BJ, UK
| | | | | | | | | | | | | | | |
Collapse
|
21
|
Abstract
We have investigated the mechanism by which high concentrations of glucose inhibit insulin stimulation of glycogen synthase. In NIH-3T3-L1 adipocytes cultured in low glucose (LG; 2.5 mm), the half-maximal activation concentration (A(0.5)) of glucose 6-phosphate was 162 +/- 15 microm. Exposure to either high glucose (HG; 20 mm) or glucosamine (GlcN; 10 mm) increased the A(0.5) to 558 +/- 61 or 612 +/- 34 microm. Insulin treatment with LG reduced the A(0.5) to 96 +/- 10 microm, but cells cultured with HG or GlcN were insulin-resistant (A(0.5) = 287 +/- 27 or 561 +/- 77 microm). Insulin resistance was not explained by increased phosphorylation of synthase. In fact, culture with GlcN decreased phosphorylation to 61% of the levels seen in cells cultured in LG. Hexosamine flux and subsequent enzymatic protein O-glycosylation have been postulated to mediate nutrient sensing and insulin resistance. Glycogen synthase is modified by O-linked N-acetylglucosamine, and the level of glycosylation increased in cells treated with HG or GlcN. Treatment of synthase in vitro with protein phosphatase 1 increased basal synthase activity from cells cultured in LG to 54% of total activity but was less effective with synthase from cells cultured in HG or GlcN, increasing basal activity to only 13 or 16%. After enzymatic removal of O-GlcNAc, however, subsequent digestion with phosphatase increased basal activity to over 73% for LG, HG, and GlcN. We conclude that O-GlcNAc modification of glycogen synthase results in the retention of the enzyme in a glucose 6-phosphate-dependent state and contributes to the reduced activation of the enzyme in insulin resistance.
Collapse
Affiliation(s)
- Glendon J Parker
- Veterans Affairs Medical Center and Division of Endocrinology, University of Utah School of Medicine, Salt Lake City 84132, USA
| | | | | | | |
Collapse
|
22
|
Covington M, Crawford TM, Parker GJ. Time-resolved measurement of propagating spin waves in ferromagnetic thin films. Phys Rev Lett 2002; 89:237202. [PMID: 12485035 DOI: 10.1103/physrevlett.89.237202] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2002] [Indexed: 05/24/2023]
Abstract
We measure the propagation of spatially localized spin waves in NiFe thin films through local inductive detection of the dynamic magnetization. A pulsed magnetic field excites a linear superposition of spin wave modes with a distribution that is predominantly driven by the spatial dependence of the in-plane excitation field. The results of numerical micromagnetic calculations exhibit excellent agreement with experiment and show that a comprehensive account of spatial nonuniformity and propagation is necessary to accurately measure the intrinsic damping rate.
Collapse
Affiliation(s)
- M Covington
- Seagate Research, 1251 Waterfront Place, Pittsburgh, Pennsylvania 15222, USA.
| | | | | |
Collapse
|
23
|
McClain DA, Lubas WA, Cooksey RC, Hazel M, Parker GJ, Love DC, Hanover JA. Altered glycan-dependent signaling induces insulin resistance and hyperleptinemia. Proc Natl Acad Sci U S A 2002; 99:10695-9. [PMID: 12136128 PMCID: PMC125016 DOI: 10.1073/pnas.152346899] [Citation(s) in RCA: 269] [Impact Index Per Article: 12.2] [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: 11/18/2022] Open
Abstract
Insulin resistance and beta cell toxicity are key features of type 2 diabetes. One leading hypothesis suggests that these abnormalities result from excessive flux of nutrients through the UDP-hexosamine biosynthetic pathway leading to "glucose toxicity." How the products of the hexosamine pathway mediate these effects is not known. Here, we show that transgenic overexpression of an enzyme using UDP-GlcNAc to modify proteins with O-GlcNAc produces the type 2 diabetic phenotype. Even modest overexpression of an isoform of O-GlcNAc transferase, in muscle and fat, leads to insulin resistance and hyperleptinemia. These data support the proposal that O-linked GlcNAc transferase participates in a hexosamine-dependent signaling pathway that is linked to insulin resistance and leptin production.
Collapse
Affiliation(s)
- Donald A McClain
- Department of Medicine, University of Utah and Veterans Affairs Medical Center, Salt Lake City, UT 84112, USA
| | | | | | | | | | | | | |
Collapse
|
24
|
Coulon O, Hickman SJ, Parker GJ, Barker GJ, Miller DH, Arridge SR. Quantification of spinal cord atrophy from magnetic resonance images via a B-spline active surface model. Magn Reson Med 2002; 47:1176-85. [PMID: 12111964 DOI: 10.1002/mrm.10162] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.4] [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: 11/06/2022]
Abstract
A method is presented that aims at segmenting and measuring the surface of the spinal cord from MR images in order to detect and quantify atrophy. A semiautomatic segmentation with very little intervention from an operator is proposed. It is based on the optimization of a B-spline active surface. The method allows for the computation of orthogonal cross-sections at any level along the cord, from which measurements are derived, such as cross-sectional area or curvature. An evaluation of the accuracy and reproducibility of the method is presented.
Collapse
Affiliation(s)
- O Coulon
- Department of Computer Science, University College London, London, UK.
| | | | | | | | | | | |
Collapse
|
25
|
Parker GJ, Barker GJ, Tofts PS. Accurate multislice gradient echo T(1) measurement in the presence of non-ideal RF pulse shape and RF field nonuniformity. Magn Reson Med 2001; 45:838-45. [PMID: 11323810 DOI: 10.1002/mrm.1112] [Citation(s) in RCA: 89] [Impact Index Per Article: 3.9] [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: 11/06/2022]
Abstract
A methodology is presented for estimating T(1) using a two-point technique with a standard multislice gradient echo sequence. The method explicitly corrects for the shape of the RF pulse and for spatial variations in transmitted RF field intensity. Including these factors in the calculation of T(1) gives a substantial improvement in accuracy and precision of two-point gradient echo T(1) measurements in the presence of RF nonuniformity and non-ideal pulse profiles. The mean accuracy of the technique was found to be 1.4%. The mean precision was found to be 3.0%. The mean variation along the axis of a head coil was found to be 2.3%.
Collapse
Affiliation(s)
- G J Parker
- NMR Research Unit, Department of Clinical Neurology, Institute of Neurology, University College London, Queen Square, London, UK.
| | | | | |
Collapse
|
26
|
Ciccarelli O, Werring DJ, Wheeler-Kingshott CA, Barker GJ, Parker GJ, Thompson AJ, Miller DH. Investigation of MS normal-appearing brain using diffusion tensor MRI with clinical correlations. Neurology 2001; 56:926-33. [PMID: 11294931 DOI: 10.1212/wnl.56.7.926] [Citation(s) in RCA: 223] [Impact Index Per Article: 9.7] [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: 11/15/2022] Open
Abstract
OBJECTIVE To quantitatively investigate water diffusion changes in normal-appearing white matter (NAWM) and gray matter in patients with MS, and to evaluate whether these changes are correlated with clinical disability and disease duration. BACKGROUND Diffusion tensor imaging provides quantitative information about the magnitude and directionality (anisotropy) of water diffusion in vivo and detects pathologic changes in MS brain tissue. METHODS Diffusion tensor imaging was performed in 39 patients with MS and in 21 age-matched control subjects. Quantitative indices, including fractional anisotropy, volume ratio, and mean diffusivity, were obtained in 30 regions of interest located in normal-appearing basal ganglia, cerebellar gray matter, and supratentorial and infratentorial NAWM. RESULTS Patients with MS showed significantly reduced anisotropy and a trend toward increased diffusivity in the infratentorial and supratentorial NAWM, and significantly increased anisotropy in the basal ganglia. In all patients with MS, both fractional anisotropy and mean diffusivity in the cerebral peduncles were inversely correlated with the Expanded Disability Status Scale and pyramidal functional scores. In patients with relapsing-remitting MS, there was a strong correlation between Expanded Disability Status Scale score and fractional anisotropy in both supratentorial and infratentorial NAWM. In primary and secondary progressive MS, disease duration correlated strongly with mean diffusivity in infratentorial NAWM and fractional anisotropy in the cerebral peduncles, respectively. CONCLUSION The most striking finding of decreased fractional anisotropy in supratentorial and infratentorial NAWM and increased fractional anisotropy in basal ganglia may result from axonal degeneration due to fiber transection in remote focal lesions. Diffusion tensor imaging indices, in particular fractional anisotropy, appear sensitive to structural damage in NAWM that is associated with disability and progression in MS.
Collapse
Affiliation(s)
- O Ciccarelli
- NMR Research Unit, Institute of Neurology, National Hospital for Neurology and Neurosurgery, London, United Kingdom
| | | | | | | | | | | | | |
Collapse
|
27
|
Wieshmann UC, Krakow K, Symms MR, Parker GJ, Clark CA, Barker GJ, Shorvon SD. Combined functional magnetic resonance imaging and diffusion tensor imaging demonstrate widespread modified organisation in malformation of cortical development. J Neurol Neurosurg Psychiatry 2001; 70:521-3. [PMID: 11254780 PMCID: PMC1737316 DOI: 10.1136/jnnp.70.4.521] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
A patient with a mild left hemiparesis and a malformation of cortical development in the right hemisphere was investigated with fMRI (functional magnetic resonance imaging) and DTI (diffusion tensor imaging). The motor cortex was studied using a finger tapping fMRI experiment. The fibre orientation was studied by displaying the principal eigenvector of the diffusion tensor in the spatially normalised brain of the patient and of control subjects. In addition, the anisotropy (directionality) of water diffusion of the patient was statistically compared with control subjects. The malformation was located in the right central region in the expected position of the motor cortex. fMRI showed activation anterior and posterior to the malformation. DTI disclosed that fibres with rostrocaudal orientation, presumably representing the pyramidal tract, were deviating from their normal orientation and passing around the malformation. There were widespread regions of reduced anisotropy affecting both hemispheres. In conclusion, fMRI and DTI provided concordant information showing widespread modified functional and structural organisation including regions which appeared normal on standard imaging.
Collapse
Affiliation(s)
- U C Wieshmann
- NSE Epilepsy Research MRI Unit, Epilepsy Research Group, Department of Clinical Neurology, Institute of Neurology, UCL, Queen Square, London WC1N3BG, UK.
| | | | | | | | | | | | | |
Collapse
|
28
|
Gao Y, Wells L, Comer FI, Parker GJ, Hart GW. Dynamic O-glycosylation of nuclear and cytosolic proteins: cloning and characterization of a neutral, cytosolic beta-N-acetylglucosaminidase from human brain. J Biol Chem 2001; 276:9838-45. [PMID: 11148210 DOI: 10.1074/jbc.m010420200] [Citation(s) in RCA: 490] [Impact Index Per Article: 21.3] [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: 11/06/2022] Open
Abstract
Dynamic modification of cytoplasmic and nuclear proteins by O-linked N-acetylglucosamine (O-GlcNAc) on Ser/Thr residues is ubiquitous in higher eukaryotes and is analogous to protein phosphorylation. The enzyme for the addition of this modification, O-GlcNAc transferase, has been cloned from several species. Here, we have cloned a human brain O-GlcNAcase that cleaves O-GlcNAc off proteins. The cloned cDNA encodes a polypeptide of 916 amino acids with a predicted molecular mass of 103 kDa and a pI value of 4.63, but the protein migrates as a 130-kDa band on SDS-polyacrylamide gel electrophoresis. The cloned O-GlcNAcase has a pH optimum of 5.5-7.0 and is inhibited by GlcNAc but not by GalNAc. p-Nitrophenyl (pNP)-beta-GlcNAc, but not pNP-beta-GalNAc or pNP-alpha-GlcNAc, is a substrate. The cloned enzyme cleaves GlcNAc, but not GalNAc, from glycopeptides. Cell fractionation suggests that the overexpressed protein is mostly localized in the cytoplasm. It therefore has all the expected characteristics of O-GlcNAcase and is distinct from lysosomal hexosaminidases. Northern blots show that the transcript is expressed in every human tissue examined but is the highest in the brain, placenta, and pancreas. An understanding of O-GlcNAc dynamics and O-GlcNAcase may be key to elucidating the relationships between O-phosphate and O-GlcNAc and to the understanding of the molecular mechanisms of diseases such as diabetes, cancer, and neurodegeneration.
Collapse
MESH Headings
- Acetylglucosaminidase/chemistry
- Acetylglucosaminidase/genetics
- Acetylglucosaminidase/isolation & purification
- Amino Acid Sequence
- Amino Acids/chemistry
- Ammonium Sulfate/pharmacology
- Animals
- Blotting, Northern
- Blotting, Western
- Brain/metabolism
- COS Cells
- Cattle
- Cell Fractionation
- Cell Nucleus/metabolism
- Chromatography, Agarose
- Chromatography, DEAE-Cellulose
- Chromatography, Ion Exchange
- Cloning, Molecular
- Concanavalin A/chemistry
- Conserved Sequence
- Cytosol/metabolism
- DNA, Complementary/metabolism
- Databases, Factual
- Dose-Response Relationship, Drug
- Electrophoresis, Polyacrylamide Gel
- Evolution, Molecular
- Glycosylation
- Humans
- Hydrogen-Ion Concentration
- Lysosomes/enzymology
- Mass Spectrometry
- Molecular Sequence Data
- Recombinant Proteins/chemistry
- Recombinant Proteins/metabolism
- Sequence Homology, Amino Acid
- Silver Staining
- Sodium Chloride/pharmacology
- Transfection
- beta-N-Acetylhexosaminidases/chemistry
Collapse
Affiliation(s)
- Y Gao
- Department of Biological Chemistry, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21205-2185, USA
| | | | | | | | | |
Collapse
|
29
|
Netti MC, Harris A, Baumberg JJ, Whittaker DM, Charlton MB, Zoorob ME, Parker GJ. Optical trirefringence in photonic crystal waveguides. Phys Rev Lett 2001; 86:1526-1529. [PMID: 11290184 DOI: 10.1103/physrevlett.86.1526] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/11/2000] [Indexed: 05/23/2023]
Abstract
We demonstrate that 2D photonic crystals can possess optical trirefringence in which there are six field orientations for which linear incident light is not perturbed on reflection or transmission. Such a property is rigorously forbidden in homogeneous nonmagnetic dielectrics which can possess only optical birefringence. We experimentally demonstrate this phenomena in silicon-based mesostructures formed from photonic crystal waveguides embedded in a Fabry-Perot cavity. Multirefringence is controlled by the presence of submicron dielectric patterning and is well explained by an exact scattering matrix theory.
Collapse
Affiliation(s)
- M C Netti
- Department of Physics & Astronomy, University of Southampton, SO17 1BJ, United Kingdom
| | | | | | | | | | | | | |
Collapse
|
30
|
Kapeller P, McLean MA, Griffin CM, Chard D, Parker GJ, Barker GJ, Thompson AJ, Miller DH. Preliminary evidence for neuronal damage in cortical grey matter and normal appearing white matter in short duration relapsing-remitting multiple sclerosis: a quantitative MR spectroscopic imaging study. J Neurol 2001; 248:131-8. [PMID: 11284131 DOI: 10.1007/s004150170248] [Citation(s) in RCA: 94] [Impact Index Per Article: 4.1] [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: 10/27/2022]
Abstract
Neuronal damage and loss is likely to underlie irreversible disability in multiple sclerosis (MS). The time of onset, location and extent of neuronal damage in early disease are all uncertain. To explore this issue 16 patients with short duration, mild relapsing-remitting disease (mean disease duration 1.8 years, median EDSS 1) were studied using short echo time proton magnetic resonance spectroscopic imaging (1H-MRSI) to quantify the concentration of the neuronal marker N-acetyl-aspartate (NAA). The data were compared with those from 12 age-matched controls. 1H-MRSI was obtained from a 1.5-cm-thick slice just above the lateral ventricles. The Linear Combination (LC) Model combined with locally developed software allowed automated measurement of absolute metabolite concentrations from lesions, normal-appearing white matter (NAWM) and cortical grey matter (CGM). MS CGM exhibited significantly lower NAA (P = 0.01) and myo-inositol (P = 0.04) than control CGM. MS NAWM exhibited a lower concentration of NAA (P = 0.01) and increased myo-inositol (P = 0.03) than control white matter. More marked reductions in NAA and increases in myo-inositol were seen in lesions. The reduced NAA in MS CGM and NAWM suggest that mild but widespread neuronal dysfunction or loss occurs early in the course of relapsing-remitting MS. This preliminary finding should be confirmed in a larger cohort, and follow-up studies are also needed to determine the prognostic and pathophysiological significance of these early changes.
Collapse
Affiliation(s)
- P Kapeller
- NMR Research Unit, Institute of Neurology, University College London, Queen Square, London WC1N 3BG, UK
| | | | | | | | | | | | | | | |
Collapse
|
31
|
Padhani AR, MacVicar AD, Gapinski CJ, Dearnaley DP, Parker GJ, Suckling J, Leach MO, Husband JE. Effects of androgen deprivation on prostatic morphology and vascular permeability evaluated with mr imaging. Radiology 2001; 218:365-74. [PMID: 11161148 DOI: 10.1148/radiology.218.2.r01ja04365] [Citation(s) in RCA: 129] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
PURPOSE To assess magnetic resonance (MR) measures of vascular permeability of prostate cancer treated with androgen deprivation and to correlate these with morphologic appearances and serum prostate-specific antigen (PSA) levels. MATERIALS AND METHODS MR examinations in 56 consecutive patients with prostate cancer were performed before and after luteinizing hormone-releasing hormone analog treatment. T2-weighted and contrast medium-enhanced T1-weighted MR images were obtained. Pre- and posttreatment comparisons of morphologic features, glandular volume, and enhancement-related parameters (capillary permeability, leakage space, gadolinium accumulation) were made. RESULTS Fifty-five tumors were seen before treatment; 42, after treatment. Signal intensity in the peripheral zone and seminal vesicles decreased on T2-weighted images in 42 (75%) and 25 (45%) patients, respectively. Median volume in tumor decreased by 65% (95% CI: 55%, 76%); in central gland, by 30% (95% CI: 25%, 35%). Reductions in tumor permeability (P <.001) and changes in washout patterns were observed (P <.001). Tumor permeability reductions coincided with a decrease in serum PSA levels in 91% of patients. A weak correlation between tumor permeability and volume change was seen (r = 0.55, P =.04). Reductions in peripheral zone (P <.001) and central gland (P =.009) permeability were noted. CONCLUSION Androgen deprivation decreases tumor volume and vascular permeability and impairs detection of prostate cancers. Use of MR estimates of permeability may be an additional way of assessing prostatic tumor response to antiandrogen treatment.
Collapse
Affiliation(s)
- A R Padhani
- CRC Clinical Magnetic Resonance Research Group and Academic Department of Radiotherapy, Institute of Cancer Research and Royal Marsden NHS Trust, Sutton, Surrey, England.
| | | | | | | | | | | | | | | |
Collapse
|
32
|
Gao Y, Parker GJ, Hart GW. Streptozotocin-induced beta-cell death is independent of its inhibition of O-GlcNAcase in pancreatic Min6 cells. Arch Biochem Biophys 2000; 383:296-302. [PMID: 11185566 DOI: 10.1006/abbi.2000.2094] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.0] [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: 11/22/2022]
Abstract
Streptozotocin (STZ) injection into experimental animals selectively causes massive beta-cell death. The mechanism of this specific toxicity is not fully understood. Recently, it has been discovered that O-linked N-acetylglucosamine (O-GlcNAc) is enriched in the beta-cells. It has been proposed that STZ toxicity may be due to its inhibition of neutral O-GlcNAcase activity, the enzyme that removes O-GlcNAc from cytosolic proteins (K. Liu et al., 2000, Proc. Natl. Acad. Sci. USA 97, 2820-2825). To further ascertain the role of O-GlcNAcase in beta-cell death, we have used PUGNAc, a potent and specific O-GlcNAcase inhibitor, together with STZ in pancreatic Min6 cells. Both STZ and PUGNAc increased O-GlcNAc to similar levels on intracellular proteins. STZ, but not PUGNAc, decreased cellular protein synthesis by 66.0% within 8 h, killed 80.9% of the cells within 18 h, and decreased insulin secretion. STZ, but not PUGNAc, also caused genomic DNA fragmentation, suggesting that some of the cells were undergoing apoptosis. Prolonged treatment with PUGNAc (72 h) maintained high intracellular O-GlcNAc levels, but did not result in any apparent cell damage. Furthermore, the toxicity of STZ can be largely reversed by 3-aminobenzamide, a poly(ADP-ribose) polymerase inhibitor. These data strongly indicate that STZ-induced beta-cell death is not caused by elevated intracellular O-GlcNAc levels, but instead likely involves poly(ADP-ribose) polymerase in the mechanism.
Collapse
Affiliation(s)
- Y Gao
- Department of Biological Chemistry, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21205-2185, USA
| | | | | |
Collapse
|
33
|
Abstract
MTR and T1 relaxation times are abnormal in MS lesions and NAWM, and may reflect tissue damage such as demyelination and axonal loss. Their relationship and potential to provide complementary information in tissue characterisation is explored. The aim of this study was to document the relationship between magnetisation transfer ratio (MTR) and T1 relaxation time in Multiple Sclerosis (MS) lesions and normal appearing white matter (NAWM) in order to determine whether the combination provides a more comprehensive tissue characterisation than either parameter in isolation. Ten patients with relapsing remitting MS and 10 age matched healthy controls underwent imaging using a protocol which included the measurement of both MTR and T1 relaxation times. The MTR and T1 values were compared statistically using a commonly adopted correlation approach and a mixed-model regression approach. There was a strong correlation between MTR and T1 in MS lesions (r=0.74). The correlation was seen equally in T1 hypointense and isointense lesions. The relationship was much weaker in MS NAWM (r=0.24) and no correlation was found in control white matter (r=0.06). Mixed-model regression analysis confirmed that the relationship between T1 and MTR is strongly dependent upon tissue type (MS lesion, MS NAWM, or control white matter). The relationship between MTR and T1 relaxation time measurements varies markedly between pathological and normal tissue types. In MS, the complementary information obtained from MTR and T1 is most apparent in NAWM. The results emphasise the potential for combinations of MR parameters to improve tissue characterisation, which in turn should improve understanding of disease pathology and treatment monitoring. Multiple Sclerosis (2000) 6 327 - 331
Collapse
Affiliation(s)
- C M Griffin
- NMR Research Group, Institute of Neurology, National Hospital for Neurology and Neurosurgery, Queen Square, London WC1N 3BG, UK
| | | | | | | | | |
Collapse
|
34
|
Stevenson VL, Parker GJ, Barker GJ, Birnie K, Tofts PS, Miller DH, Thompson AJ. Variations in T1 and T2 relaxation times of normal appearing white matter and lesions in multiple sclerosis. J Neurol Sci 2000; 178:81-7. [PMID: 11018698 DOI: 10.1016/s0022-510x(00)00339-7] [Citation(s) in RCA: 86] [Impact Index Per Article: 3.6] [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
OBJECTIVE To investigate the variation in T1 and T2 relaxation times of normal appearing white matter (NAWM) and lesions in multiple sclerosis (MS) throughout the brain. BACKGROUND The magnetic resonance imaging (MRI) sequence fast FLAIR (fluid attenuated inversion recovery) has demonstrated overall increased lesion detection when compared to conventional or fast spin echo (FSE) but fewer lesions in the posterior fossa and spinal cord. The reasons for this are unknown, but may be due to variations in the T1 and T2 relaxation times within NAWM and MS lesions. METHOD Ten patients and 10 controls underwent MRI of the brain which involved FSE, fast FLAIR and the measurement of T1 and T2 relaxation times. RESULTS Of 151 lesions analysed (22 infra-tentorial, 129 supra-tentorial), eight were missed by the fast FLAIR sequence. T1 and T2 relaxation times in normal controls were longer in the infra-tentorial, than supra-tentorial, region. Patient NAWM relaxation times were prolonged compared with control values in both regions. Lesions demonstrated longer relaxation times than either control white matter or patient NAWM in both regions, however this difference was less marked infra-tentorially. The eight posterior fossa lesions not visible on the fast FLAIR sequence were characterised by short T1 and T2 relaxation times which overlapped with the patient NAWM for both T1 and T2 and with control values for T2 relaxation times. CONCLUSION Both lesion and NAWM relaxation time characteristics vary throughout the brain. The T1 and T2 relaxation times of infra-tentorial lesions are closer to the relaxation times of local NAWM than supra-tentorial lesions, resulting in reduced contrast between posterior fossa lesions and the background NAWM. Consequently the characteristics of some lesions overlap with those of NAWM resulting in reduced conspicuity. By utilising this information, it may be possible to optimise fast FLAIR sequences to improve infra-tentorial lesion detection.
Collapse
Affiliation(s)
- V L Stevenson
- NMR Research Unit, Institute of Neurology, Queen Square, WC1N 3BG, London, UK
| | | | | | | | | | | | | |
Collapse
|
35
|
Brown J, Buckley D, Coulthard A, Dixon AK, Dixon JM, Easton DF, Eeles RA, Evans DG, Gilbert FG, Graves M, Hayes C, Jenkins JP, Jones AP, Keevil SF, Leach MO, Liney GP, Moss SM, Padhani AR, Parker GJ, Pointon LJ, Ponder BA, Redpath TW, Sloane JP, Turnbull LW, Walker LG, Warren RM. Magnetic resonance imaging screening in women at genetic risk of breast cancer: imaging and analysis protocol for the UK multicentre study. UK MRI Breast Screening Study Advisory Group. Magn Reson Imaging 2000; 18:765-76. [PMID: 11027869 DOI: 10.1016/s0730-725x(00)00167-3] [Citation(s) in RCA: 91] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
The imaging and analysis protocol of the UK multicentre study of magnetic resonance imaging (MRI) as a method of screening for breast cancer in women at genetic risk is described. The study will compare the sensitivity and specificity of contrast-enhanced MRI with two-view x-ray mammography. Approximately 500 women below the age of 50 at high genetic risk of breast cancer will be recruited per year for three years, with annual MRI and x-ray mammography continuing for up to 5 years. A symptomatic cohort will be measured in the first year to ensure consistent reporting between centres. The MRI examination comprises a high-sensitivity three-dimensional contrast-enhanced assessment, followed by a high-specificity contrast-enhanced study in equivocal cases. Multiparametric analysis will encompass morphological assessment, the kinetics of contrast agent uptake and determination of quantitative pharmacokinetic parameters. Retrospective analysis will identify the most specific indicators of malignancy. Sensitivity and specificity, together with diagnostic performance, diagnostic impact and therapeutic impact will be assessed with reference to pathology, follow-up and changes in diagnostic certainty and therapeutic decisions. Mammography, lesion localisation, pathology and cytology will be performed in accordance with the UK NHS Breast Screening Programme quality assurance standards. Similar standards of quality assurance will be applied for MR measurements and evaluation.
Collapse
Affiliation(s)
- J Brown
- Health Economics Research Group, Brunel University, Middlesex, UK
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
36
|
Werring DJ, Toosy AT, Clark CA, Parker GJ, Barker GJ, Miller DH, Thompson AJ. Diffusion tensor imaging can detect and quantify corticospinal tract degeneration after stroke. J Neurol Neurosurg Psychiatry 2000; 69:269-72. [PMID: 10896709 PMCID: PMC1737065 DOI: 10.1136/jnnp.69.2.269] [Citation(s) in RCA: 287] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Diffusion tensor imaging (DTI) fully characterises water molecule mobility in vivo, allowing an exploration of fibre tract integrity and orientation in the human brain. Using DTI this study demonstrates reduced fibre coherence (anisotropy) associated with cerebral infarction and in the corticospinal tract remote from the lesion, in five patients 2 to 6 months after ischaemic stroke. The study highlights the potential of DTI to detect and monitor the structural degeneration of fibre pathways, which may provide a better understanding of the pattern of clinical evolution after stroke.
Collapse
Affiliation(s)
- D J Werring
- NMR Research Unit, Institute of Neurology, Queen Square, London WC1N 3BG, UK
| | | | | | | | | | | | | |
Collapse
|
37
|
Gómez-Ansón B, MacManus DG, Parker GJ, Davie CA, Barker GJ, Moseley IF, McDonald WI, Miller DH. In vivo 1H-magnetic resonance spectroscopy of the spinal cord in humans. Neuroradiology 2000; 42:515-7. [PMID: 10952184 DOI: 10.1007/s002340000323] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.5] [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: 10/27/2022]
Abstract
Magnetic resonance spectroscopy (MRS) has been used in a variety of conditions affecting the central nervous system. Until now, only the brain has been studied, and spectroscopy of the spinal cord has not been previously reported. During the past 12 months, we have been experimenting with MRS of the cervical spinal cord of healthy volunteers. We present this technique, its current limitations, and possible future technological improvements and potential applications.
Collapse
Affiliation(s)
- B Gómez-Ansón
- NMR Research Unit, Institute of Neurology, University College London, UK.
| | | | | | | | | | | | | | | |
Collapse
|
38
|
Abstract
Calculation and sorting of the eigenvectors of diffusion using diffusion tensor imaging has previously been shown to be sensitive to noise levels in the acquired data. This sensitivity manifests as random and systematic errors in the diffusion eigenvalues and derived parameters such as indices of anisotropy. An optimized application of nonlinear smoothing techniques to diffusion data prior to calculation of the diffusion tensor is shown to reduce both random and systematic errors, while causing little blurring of anatomical structures. Conversely, filtering applied to calculated images of fractional anisotropy is shown to fail in reducing systematic errors and in recovering anatomical detail. Using both real and simulated brain data sets, it is demonstrated that this approach has the potential to allow acquisition of data that would otherwise be too noisy to be of use.
Collapse
Affiliation(s)
- G J Parker
- NMR Research Unit, University Department of Clinical Neurology, Institute of Neurology, University College London, London WC1N 3BG, United Kingdom.
| | | | | | | | | |
Collapse
|
39
|
Tofts PS, Lloyd D, Clark CA, Barker GJ, Parker GJ, McConville P, Baldock C, Pope JM. Test liquids for quantitative MRI measurements of self-diffusion coefficient in vivo. Magn Reson Med 2000. [PMID: 10725879 DOI: 10.1002/(sici)1522-2594(200003)43:3<368::aid-mrm8>3.0.co;2-b] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
A range of liquids suitable as quality control test objects for measuring the accuracy of clinical MRI diffusion sequences (both apparent diffusion coefficient and tensor) has been identified and characterized. The self-diffusion coefficients for 15 liquids (3 cyclic alkanes: cyclohexane to cyclooctane, 9 n-alkanes: n-octane to n-hexadecane, and 3 n-alcohols: ethanol to 1-propanol were measured at 15-30 degrees C using an NMR spectrometer. Values at 22 degrees C range from 0.36 to 2.2 10(-9) m(2)s(-1). Typical 95% confidence limits are +/-2%. Temperature coefficients are 1.7-3.2% degrees C. T1 and T2 values at 1.5 T and proton density are given. n-tridecane has a diffusion coefficient close to that of normal white matter. The longer n-alkanes may be useful T2 standards. Measurements from a spin-echo MRI sequence agreed to within 2%.
Collapse
Affiliation(s)
- P S Tofts
- Department of Clinical Neurology, Institute of Neurology, University College London, UK.
| | | | | | | | | | | | | | | |
Collapse
|
40
|
Leary SM, Brex PA, MacManus DG, Parker GJ, Barker GJ, Miller DH, Thompson AJ. A (1)H magnetic resonance spectroscopy study of aging in parietal white matter: implications for trials in multiple sclerosis. Magn Reson Imaging 2000; 18:455-9. [PMID: 10788723 DOI: 10.1016/s0730-725x(00)00131-4] [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: 10/18/2022]
Abstract
1H magnetic resonance spectroscopy (MRS) provides a unique tool to detect and quantify brain metabolites. In multiple sclerosis it can be used to investigate axonal loss or dysfunction through measurement of N-acetyl aspartate (NAA), a neuronal marker. Previous studies in adults have reported variable effects of aging on metabolite concentrations but have predominantly focused on changes in the elderly. This study has examined a younger adult age group to provide a reference database more applicable to the multiple sclerosis population. Single voxel (1)H MRS was carried out in 44 subjects between 22 and 62 years of age. Sixteen subjects underwent repeat examination after one year. Absolute concentrations of NA (the sum of NAA and N-acetyl aspartate glutamate), NAA, creatine/phosphocreatine (Cr), choline containing compounds (Cho) and myo-inositol (mI) were measured. NA, NAA and mI concentrations did not correlate with age but there were significant correlations between age and Cr (r = 0.43, p = 0.004) and Cho (r = 0.38, p = 0. 011) concentrations. No significant differences in metabolite concentrations were seen over one year. This study provides evidence that age-related changes of metabolite concentrations occur even in a young to middle aged adult population. This emphasizes the need to perform absolute quantification of metabolite concentrations rather than ratios and the importance of age-matching in (1)H MRS studies of multiple sclerosis.
Collapse
Affiliation(s)
- S M Leary
- NMR Research Unit, Institute of Neurology, Queen Square, London, UK.
| | | | | | | | | | | | | |
Collapse
|
41
|
Brex PA, Parker GJ, Leary SM, Molyneux PD, Barker GJ, Davie CA, Thompson AJ, Miller DH. Lesion heterogeneity in multiple sclerosis: a study of the relations between appearances on T1 weighted images, T1 relaxation times, and metabolite concentrations. J Neurol Neurosurg Psychiatry 2000; 68:627-32. [PMID: 10766895 PMCID: PMC1736901 DOI: 10.1136/jnnp.68.5.627] [Citation(s) in RCA: 87] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
OBJECTIVES Multiple sclerosis lesions appear as areas of high signal on T2 weighted MRI. A proportion of these lesions, when viewed on T1 weighted MRI, appear hypointense compared with surrounding white matter. These hypointense T1 lesions are thought to represent areas of greater tissue damage compared with the more non-specific, total T2 lesion load. This study aimed to better characterise the properties of high signal T2 lesions with differing appearances on T1 weighted MRI using quantitative MR techniques. METHODS Eleven patients with secondary progressive multiple sclerosis were studied. Two high signal T2 lesions were selected from each patient-one of which appeared hypointense and one isointense on a T1 weighted image. A voxel was positioned around each lesion and for this volume of brain the metabolite concentrations were estimated using proton MR spectroscopy ((1)H-MRS) and the T1 relaxation time within each voxel calculated from a T1 map generated using a multislice technique. RESULTS Compared with isointense T1 lesions, hypointense T1 lesions exhibited a significantly lower absolute concentration of N-acetyl derived metabolites (tNAA) and a significantly higher absolute concentration of myo-inositol (Ins). T1 relaxation time correlated significantly with both tNAA (r=-0.8, p < 0.001) and Ins (r=0.5, p=0. 012). There was no correlation between T1 relaxation times and creatine/phosphocreatine or choline containing compounds. CONCLUSIONS Prolonged T1 relaxation times seem to reflect the severity of axonal damage or dysfunction (inferred by a low tNAA) and possibly also gliosis (inferred by a high Ins) in chronic multiple sclerosis lesions.
Collapse
Affiliation(s)
- P A Brex
- NMR Research Unit, 6th floor, Institute of Neurology, University College London, Queen Square, London WC1N 3BG, UK
| | | | | | | | | | | | | | | |
Collapse
|
42
|
Parker GJ, Law TL, Lenoch FJ, Bolger RE. Development of high throughput screening assays using fluorescence polarization: nuclear receptor-ligand-binding and kinase/phosphatase assays. J Biomol Screen 2000; 5:77-88. [PMID: 10803607 DOI: 10.1177/108705710000500204] [Citation(s) in RCA: 179] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Fluorescence polarization (FP) has been used to develop high throughput screening (HTS) assays for nuclear receptor-ligand displacement and kinase inhibition. FP is a solution-based, homogeneous technique requiring no immobilization or separation of reaction components. The FP-based estrogen receptor (ER) assay is based on the competition of fluorescein-labeled estradiol and estrogen-like compounds for binding to ER. These studies determined the Kd for this interaction to be 3 nM for ERalpha and 2 nM for ERbeta; IC50 values for 17beta-estradiol, tamoxifen, 4-OH-tamoxifen, and diethylstibestrol were determined to be 5.6, 189, 26, and 3.5 nM, respectively. In a screen of 50 lead compounds from a transcriptional activation screen, 21 compounds had IC50 values below 10 microM, with one having an almost 100-fold higher affinity for ERbeta over ERalpha. These data show that an FP-based competitive binding assay can be used to screen diverse compounds with a broad range of binding affinities for ERs. The FP-based protein-tyrosine kinase (PTK) assay uses fluorescein-labeled phosphopeptides bound to anti-phosphotyrosine antibodies. Phosphopeptides generated by a kinase compete for this binding. In c-Src kinase reactions, polarization decreased with time as reaction products displaced the fluorescein-labeled phosphopeptide from the anti-phosphotyrosine antibodies. The experimentally determined IC50 of AG 1478 was 400 pM, while Genistein did not inhibit the epidermal growth factor receptor at similar concentrations. Like the FP-based PTK assay, the protein kinase C (PKC) assay utilizes competition. PKC isoforms had different turnover rates for the peptide substrate. The IC50 for staurosporine was less than 10 nM for all PKC isoforms. Tyrosine phosphatase assays use direct binding rather than competition. Increasing concentrations of T-cell protein-tyrosine phosphatase (TC PTP) increased the rate of dephosphorylation. This change in polarization was dependent on TC PTP and was inhibited by 50 microM Na3VO4. The IC50 of Na3VO4 was 4 nM for TC PTP. These data demonstrate that a FP-based assay can detect kinase and phosphatase activity. Homogeneous, fluorescent techniques such as FP are now methods of choice for screening many types of drug targets. New HTS instrumentation and assay methods like these make FP a technology easily incorporated into HTS.
Collapse
Affiliation(s)
- G J Parker
- PanVera Corporation, Madison, WI 53711, USA.
| | | | | | | |
Collapse
|
43
|
Wieshmann UC, Symms MR, Parker GJ, Clark CA, Lemieux L, Barker GJ, Shorvon SD. Diffusion tensor imaging demonstrates deviation of fibres in normal appearing white matter adjacent to a brain tumour. J Neurol Neurosurg Psychiatry 2000; 68:501-3. [PMID: 10727488 PMCID: PMC1736891 DOI: 10.1136/jnnp.68.4.501] [Citation(s) in RCA: 102] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The objective was to study fibre orientation in the cerebral white matter of a patient with a brain tumour using diffusion tensor imaging (DTI). A patient with a mild left hemiparesis and a tumour in the right frontal lobe and 20 healthy volunteers were scanned with a DTI sequence. The scans were spatially normalised and the fibre orientation in the patient compared with the fibre orientation in normal controls. DTI disclosed a change of the orientation of fibres in the patient compared with normal controls. In the normal appearing white matter adjacent to the tumour fibres deviated from the normal superior inferior orientation in the corona radiata by about 30 degrees. This finding was consistent with a displacement by distant mass effect rather than a destruction of fibres, in agreement with the neurological examination. In conclusion, DTI demonstrated a deviation of fibres in normal appearing white matter adjacent to a tumour. The technique will improve understanding of the effects of structural abnormalities on fibres. This will assist the interpretation of clinical findings and functional imaging studies and guide neurosurgical interventions.
Collapse
Affiliation(s)
- U C Wieshmann
- Epilepsy Research Group, Department of Clinical Neurology, Institute of Neurology, University College London, Queen Square, London WC1N3BG, UK.
| | | | | | | | | | | | | |
Collapse
|
44
|
Abstract
A range of liquids suitable as quality control test objects for measuring the accuracy of clinical MRI diffusion sequences (both apparent diffusion coefficient and tensor) has been identified and characterized. The self-diffusion coefficients for 15 liquids (3 cyclic alkanes: cyclohexane to cyclooctane, 9 n-alkanes: n-octane to n-hexadecane, and 3 n-alcohols: ethanol to 1-propanol were measured at 15-30 degrees C using an NMR spectrometer. Values at 22 degrees C range from 0.36 to 2.2 10(-9) m(2)s(-1). Typical 95% confidence limits are +/-2%. Temperature coefficients are 1.7-3.2% degrees C. T1 and T2 values at 1.5 T and proton density are given. n-tridecane has a diffusion coefficient close to that of normal white matter. The longer n-alkanes may be useful T2 standards. Measurements from a spin-echo MRI sequence agreed to within 2%.
Collapse
Affiliation(s)
- P S Tofts
- Department of Clinical Neurology, Institute of Neurology, University College London, UK.
| | | | | | | | | | | | | | | |
Collapse
|
45
|
Parker GJ, Baustert I, Tanner SF, Leach MO. Improving image quality and T(1) measurements using saturation recovery turboFLASH with an approximate K-space normalisation filter. Magn Reson Imaging 2000; 18:157-67. [PMID: 10722976 DOI: 10.1016/s0730-725x(99)00124-1] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.5] [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: 11/21/2022]
Abstract
We present a method for reducing the image point-spread function and measuring T(1) using saturation recovery turboFLASH (SRTF) with centric-ordered k-space and a k-space correction filter designed to compensate for longitudinal magnetisation evolution during image acquisition. The method provides a two point T(1) measurement that reduces inaccuracies and image artefacts caused by longitudinal magnetisation evolution in conventional turboFLASH methods. The method is designed for use in rapid, quantitative measurements of contrast agent uptake in vivo.
Collapse
Affiliation(s)
- G J Parker
- Cancer Research Campaign Clinical Magnetic Resonance Research Group, Institute of Cancer Research and Royal Marsden NHS Trust, Downs Road, Sutton, Surrey, UK
| | | | | | | |
Collapse
|
46
|
Padhani AR, Gapinski CJ, Macvicar DA, Parker GJ, Suckling J, Revell PB, Leach MO, Dearnaley DP, Husband JE. Dynamic contrast enhanced MRI of prostate cancer: correlation with morphology and tumour stage, histological grade and PSA. Clin Radiol 2000; 55:99-109. [PMID: 10657154 DOI: 10.1053/crad.1999.0327] [Citation(s) in RCA: 241] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
AIM To quantify MRI enhancement characteristics of normal and abnormal prostatic tissues and to correlate these with tumour stage, histological grade and tumour markers. MATERIALS AND METHODS Quantitative gradient recalled echo MR images were obtained following bolus injection of gadopentetate dimeglumine in 48 patients with prostate cancer. Turbo spin-echo T2-weighted images at the same anatomical position were reviewed for the presence of tumours (45 regions), normal peripheral zone (33 regions), and normal appearing central gland (30 regions). Time-signal intensity parameters (onset time, mean gradient and maximal amplitude of enhancement and wash-out score) and modelling parameters (permeability surface area product, lesion leakage space and maximum gadolinium concentration) were correlated with tumour stage, histological grade (Gleason score) and serum prostatic specific antigen (PSA) levels. RESULTS Significant differences were noted between peripheral zone and tumour with respect to signal intensity and modelling parameters (P = 0.0001), except onset time. No differences between central gland and tumour enhancement values were seen. There was weak correlation between MRI tumour stage and tumour vascular permeability (r(2) = 12%; P = 0.02) and maximum tumour gadolinium concentration (r(2) = 14%; P = 0.015). However, no significant correlations were seen with Gleason score or PSA levels. CONCLUSION Quantification of MR contrast enhancement characteristics allows tissue discrimination in prostate cancer consistent with known variations in microvessel density estimates.
Collapse
Affiliation(s)
- A R Padhani
- Academic Department of Radiology, Institute of Cancer Research, The Royal Marsden NHS Trust, Downs Road, Sutton, Surrey, SM2 5PT, U.K
| | | | | | | | | | | | | | | | | |
Collapse
|
47
|
Tofts PS, Brix G, Buckley DL, Evelhoch JL, Henderson E, Knopp MV, Larsson HB, Lee TY, Mayr NA, Parker GJ, Port RE, Taylor J, Weisskoff RM. Estimating kinetic parameters from dynamic contrast-enhanced T(1)-weighted MRI of a diffusable tracer: standardized quantities and symbols. J Magn Reson Imaging 1999. [PMID: 10508281 DOI: 10.1002/(sici)1522-2586(199909)10:3<223:aid-jmri2>3.0.co;2-s] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
We describe a standard set of quantity names and symbols related to the estimation of kinetic parameters from dynamic contrast-enhanced T(1)-weighted magnetic resonance imaging data, using diffusable agents such as gadopentetate dimeglumine (Gd-DTPA). These include a) the volume transfer constant K(trans) (min(-1)); b) the volume of extravascular extracellular space (EES) per unit volume of tissue v(e) (0 < v(e) < 1); and c) the flux rate constant between EES and plasma k(ep) (min(-1)). The rate constant is the ratio of the transfer constant to the EES (k(ep) = K(trans)/v(e)). Under flow-limited conditions K(trans) equals the blood plasma flow per unit volume of tissue; under permeability-limited conditions K(trans) equals the permeability surface area product per unit volume of tissue. We relate these quantities to previously published work from our groups; our future publications will refer to these standardized terms, and we propose that these be adopted as international standards.
Collapse
Affiliation(s)
- P S Tofts
- Department of Clinical Neurology, Institute of Neurology, University College London, London WC1N 3BG, United Kingdom.
| | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
48
|
Tofts PS, Brix G, Buckley DL, Evelhoch JL, Henderson E, Knopp MV, Larsson HB, Lee TY, Mayr NA, Parker GJ, Port RE, Taylor J, Weisskoff RM. Estimating kinetic parameters from dynamic contrast-enhanced T(1)-weighted MRI of a diffusable tracer: standardized quantities and symbols. J Magn Reson Imaging 1999. [PMID: 10508281 DOI: 10.1002/(sici)1522-2586(199909)10:3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
We describe a standard set of quantity names and symbols related to the estimation of kinetic parameters from dynamic contrast-enhanced T(1)-weighted magnetic resonance imaging data, using diffusable agents such as gadopentetate dimeglumine (Gd-DTPA). These include a) the volume transfer constant K(trans) (min(-1)); b) the volume of extravascular extracellular space (EES) per unit volume of tissue v(e) (0 < v(e) < 1); and c) the flux rate constant between EES and plasma k(ep) (min(-1)). The rate constant is the ratio of the transfer constant to the EES (k(ep) = K(trans)/v(e)). Under flow-limited conditions K(trans) equals the blood plasma flow per unit volume of tissue; under permeability-limited conditions K(trans) equals the permeability surface area product per unit volume of tissue. We relate these quantities to previously published work from our groups; our future publications will refer to these standardized terms, and we propose that these be adopted as international standards.
Collapse
Affiliation(s)
- P S Tofts
- Department of Clinical Neurology, Institute of Neurology, University College London, London WC1N 3BG, United Kingdom.
| | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
49
|
Tofts PS, Brix G, Buckley DL, Evelhoch JL, Henderson E, Knopp MV, Larsson HB, Lee TY, Mayr NA, Parker GJ, Port RE, Taylor J, Weisskoff RM. Estimating kinetic parameters from dynamic contrast-enhanced T(1)-weighted MRI of a diffusable tracer: standardized quantities and symbols. J Magn Reson Imaging 1999. [PMID: 10508281 DOI: 10.1002/(sici)1522-2586(199909)10:3<223::aid-jmri2>3.0.co;2-s] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
We describe a standard set of quantity names and symbols related to the estimation of kinetic parameters from dynamic contrast-enhanced T(1)-weighted magnetic resonance imaging data, using diffusable agents such as gadopentetate dimeglumine (Gd-DTPA). These include a) the volume transfer constant K(trans) (min(-1)); b) the volume of extravascular extracellular space (EES) per unit volume of tissue v(e) (0 < v(e) < 1); and c) the flux rate constant between EES and plasma k(ep) (min(-1)). The rate constant is the ratio of the transfer constant to the EES (k(ep) = K(trans)/v(e)). Under flow-limited conditions K(trans) equals the blood plasma flow per unit volume of tissue; under permeability-limited conditions K(trans) equals the permeability surface area product per unit volume of tissue. We relate these quantities to previously published work from our groups; our future publications will refer to these standardized terms, and we propose that these be adopted as international standards.
Collapse
Affiliation(s)
- P S Tofts
- Department of Clinical Neurology, Institute of Neurology, University College London, London WC1N 3BG, United Kingdom.
| | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
50
|
Leary SM, Davie CA, Parker GJ, Stevenson VL, Wang L, Barker GJ, Miller DH, Thompson AJ. 1H magnetic resonance spectroscopy of normal appearing white matter in primary progressive multiple sclerosis. J Neurol 1999; 246:1023-6. [PMID: 10631633 DOI: 10.1007/s004150050507] [Citation(s) in RCA: 97] [Impact Index Per Article: 3.9] [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: 10/28/2022]
Abstract
Recent magnetic resonance imaging (MRI) and pathological studies have indicated that axonal loss is a major contributor to disease progression in multiple sclerosis. 1H magnetic resonance spectroscopy (MRS), through measurement of N-acetyl aspartate (NAA), a neuronal marker, provides a unique tool to investigate this. Patients with primary progressive multiple sclerosis have few lesions on conventional MRI, suggesting that changes in normal appearing white matter (NAWM), such as axonal loss, may be particularly relevant to disease progression in this group. To test this hypothesis NAWM was studied with MRS, measuring the concentration of N-acetyl derived groups (NA, the sum of NAA and N-acetyl aspartyl glutamate). Single-voxel MRS using a water-suppressed PRESS sequence was carried out in 24 patients with primary progressive multiple sclerosis and in 16 age-matched controls. Ratios of metabolite to creatine concentration (Cr) were calculated in all subjects, and absolute concentrations were measured in 18 patients and all controls. NA/Cr (median 1.40, range 0.86-1.91) was significantly lower in NAWM in patients than in controls (median 1.70, range 1.27-2.14; P = 0.006), as was the absolute concentration of NA (patients, median 6.90 mM, range 4.62-10.38 mM; controls, median 7.77 mM, range 6.60-9.71 mM; P = 0.032). There was no significant difference in the absolute concentration of creatine between the groups. This study supports the hypothesis that axonal loss occurs in NAWM in primary progressive multiple sclerosis and may well be a mechanism for disease progression in this group.
Collapse
Affiliation(s)
- S M Leary
- NMR Research Unit, Institute of Neurology, London, UK
| | | | | | | | | | | | | | | |
Collapse
|