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Simpamba K, May JL, Waghat A, Attarian H, Mateyo K. Obstructive sleep apnea and excessive daytime sleepiness among commercial motor vehicle drivers in Lusaka, Zambia. J Clin Sleep Med 2023; 19:1191-1198. [PMID: 36856062 PMCID: PMC10315601 DOI: 10.5664/jcsm.10538] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2022] [Revised: 02/20/2023] [Accepted: 02/22/2023] [Indexed: 03/02/2023]
Abstract
STUDY OBJECTIVES Obstructive sleep apnea (OSA) is a risk factor for a major public health problem, car crashes, due to excessive daytime sleepiness (EDS). Commercial vehicle driving (CVD) is a hazardous occupation, having a high fatality rate worldwide. There have been no studies on EDS and OSA in Zambia despite the high rate of annual road traffic accidents (RTAs). We aim to determine the prevalence of EDS and OSA risk among CVDs in Lusaka, Zambia, to assess the impact of OSA on high RTA rates. METHODS This was a cross-sectional study. The STOP BANG questionnaire and the Epworth Sleepiness Scale were used. Consecutive sampling of drivers was done who were divided into low and high risk of OSA (HROSA). The risk factors associated with OSA in the bivariate analyses were subjected to a multivariate logistic regression model. RESULTS One hundred thirty-six drivers participated in the study (all male) with a mean age of 48 ± 5 years. The prevalence of HROSA was 22.8% out of whom 67.7% also had a EDS. Only 9.6% of the total cohort had EDS without HROSA. Using Fisher's exact test, HROSA was significantly associated with older age (> 50 years, P < .001), obesity (body mass index >30, P < .001), neck circumference of > 40 cm (P = .032), and hypertension (P < .001). Snoring and EDS were significantly associated with RTAs (P < .0001 and P = .007, respectively). CONCLUSIONS High risk of OSA and EDS are common among CMV drivers in Zambia and underdiagnosed. The risk factors for OSA are amenable to preventive interventions. CITATION Simpamba K, May JL, Waghat A, Attarian H, Mateyo K. Obstructive sleep apnea and excessive daytime sleepiness among commercial motor vehicle drivers in Lusaka, Zambia. J Clin Sleep Med. 2023;19(7):1191-1198.
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Affiliation(s)
- Kelvin Simpamba
- Department of Internal Medicine, University Teaching Hospital, Lusaka, Zambia
| | - Jasmine L. May
- Department of Neurology, Northwestern University, Chicago, Illinois
| | - Afzal Waghat
- Department of Internal Medicine, University Teaching Hospital, Lusaka, Zambia
| | - Hrayr Attarian
- Department of Neurology, Northwestern University, Chicago, Illinois
| | - Kondwelani Mateyo
- Department of Internal Medicine, University Teaching Hospital, Lusaka, Zambia
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Tang S, May JL, Lee JH. The case of a 19-year-old woman with headache, papilledema, and diplopia. Ann Clin Transl Neurol 2021; 8:2038-2039. [PMID: 34533291 PMCID: PMC8528459 DOI: 10.1002/acn3.51452] [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] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2021] [Revised: 07/23/2021] [Accepted: 07/27/2021] [Indexed: 11/10/2022] Open
Affiliation(s)
- Sheng Tang
- Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
| | - Jasmine L May
- Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
| | - Jessica H Lee
- Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
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Tommasini-Ghelfi S, Murnan K, Kouri FM, Mahajan AS, May JL, Stegh AH. Cancer-associated mutation and beyond: The emerging biology of isocitrate dehydrogenases in human disease. Sci Adv 2019; 5:eaaw4543. [PMID: 31131326 PMCID: PMC6530995 DOI: 10.1126/sciadv.aaw4543] [Citation(s) in RCA: 82] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2018] [Accepted: 04/16/2019] [Indexed: 05/12/2023]
Abstract
Isocitrate dehydrogenases (IDHs) are critical metabolic enzymes that catalyze the oxidative decarboxylation of isocitrate to α-ketoglutarate (αKG), NAD(P)H, and CO2. IDHs epigenetically control gene expression through effects on αKG-dependent dioxygenases, maintain redox balance and promote anaplerosis by providing cells with NADPH and precursor substrates for macromolecular synthesis, and regulate respiration and energy production through generation of NADH. Cancer-associated mutations in IDH1 and IDH2 represent one of the most comprehensively studied mechanisms of IDH pathogenic effect. Mutant enzymes produce (R)-2-hydroxyglutarate, which in turn inhibits αKG-dependent dioxygenase function, resulting in a global hypermethylation phenotype, increased tumor cell multipotency, and malignancy. Recent studies identified wild-type IDHs as critical regulators of normal organ physiology and, when transcriptionally induced or down-regulated, as contributing to cancer and neurodegeneration, respectively. We describe how mutant and wild-type enzymes contribute on molecular levels to disease pathogenesis, and discuss efforts to pharmacologically target IDH-controlled metabolic rewiring.
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Affiliation(s)
- Serena Tommasini-Ghelfi
- Ken and Ruth Davee Department of Neurology, The Northwestern Brain Tumor Institute, The Robert H. Lurie Comprehensive Cancer Center, Northwestern University, 303 East Superior, Chicago, IL 60611, USA
- International Institute for Nanotechnology, Northwestern University, 2145 Sheridan Road, Evanston, IL 60208, USA
| | - Kevin Murnan
- Ken and Ruth Davee Department of Neurology, The Northwestern Brain Tumor Institute, The Robert H. Lurie Comprehensive Cancer Center, Northwestern University, 303 East Superior, Chicago, IL 60611, USA
- International Institute for Nanotechnology, Northwestern University, 2145 Sheridan Road, Evanston, IL 60208, USA
| | - Fotini M. Kouri
- Ken and Ruth Davee Department of Neurology, The Northwestern Brain Tumor Institute, The Robert H. Lurie Comprehensive Cancer Center, Northwestern University, 303 East Superior, Chicago, IL 60611, USA
- International Institute for Nanotechnology, Northwestern University, 2145 Sheridan Road, Evanston, IL 60208, USA
| | - Akanksha S. Mahajan
- Ken and Ruth Davee Department of Neurology, The Northwestern Brain Tumor Institute, The Robert H. Lurie Comprehensive Cancer Center, Northwestern University, 303 East Superior, Chicago, IL 60611, USA
- International Institute for Nanotechnology, Northwestern University, 2145 Sheridan Road, Evanston, IL 60208, USA
| | - Jasmine L. May
- Ken and Ruth Davee Department of Neurology, The Northwestern Brain Tumor Institute, The Robert H. Lurie Comprehensive Cancer Center, Northwestern University, 303 East Superior, Chicago, IL 60611, USA
- International Institute for Nanotechnology, Northwestern University, 2145 Sheridan Road, Evanston, IL 60208, USA
| | - Alexander H. Stegh
- Ken and Ruth Davee Department of Neurology, The Northwestern Brain Tumor Institute, The Robert H. Lurie Comprehensive Cancer Center, Northwestern University, 303 East Superior, Chicago, IL 60611, USA
- International Institute for Nanotechnology, Northwestern University, 2145 Sheridan Road, Evanston, IL 60208, USA
- Corresponding author.
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May JL, Kouri FM, Hurley LA, Liu J, Tommasini-Ghelfi S, Ji Y, Gao P, Calvert AE, Lee A, Chandel NS, Davuluri RV, Horbinski CM, Locasale JW, Stegh AH. IDH3α regulates one-carbon metabolism in glioblastoma. Sci Adv 2019; 5:eaat0456. [PMID: 30613765 PMCID: PMC6314828 DOI: 10.1126/sciadv.aat0456] [Citation(s) in RCA: 51] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/18/2018] [Accepted: 11/26/2018] [Indexed: 05/17/2023]
Abstract
Mutation or transcriptional up-regulation of isocitrate dehydrogenases 1 and 2 (IDH1 and IDH2) promotes cancer progression through metabolic reprogramming and epigenetic deregulation of gene expression. Here, we demonstrate that IDH3α, a subunit of the IDH3 heterotetramer, is elevated in glioblastoma (GBM) patient samples compared to normal brain tissue and promotes GBM progression in orthotopic glioma mouse models. IDH3α loss of function reduces tricarboxylic acid (TCA) cycle turnover and inhibits oxidative phosphorylation. In addition to its impact on mitochondrial energy metabolism, IDH3α binds to cytosolic serine hydroxymethyltransferase (cSHMT). This interaction enhances nucleotide availability during DNA replication, while the absence of IDH3α promotes methionine cycle activity, S-adenosyl methionine generation, and DNA methylation. Thus, the regulation of one-carbon metabolism via an IDH3α-cSHMT signaling axis represents a novel mechanism of metabolic adaptation in GBM.
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Affiliation(s)
- Jasmine L. May
- Ken and Ruth Davee Department of Neurology, The Northwestern Brain Tumor Institute, The Robert H. Lurie Comprehensive Cancer Center, Northwestern University, 303 East Superior, Chicago, IL 60611, USA
- International Institute for Nanotechnology, Northwestern University, 2145 Sheridan Road, Evanston, IL 60208, USA
| | - Fotini M. Kouri
- Ken and Ruth Davee Department of Neurology, The Northwestern Brain Tumor Institute, The Robert H. Lurie Comprehensive Cancer Center, Northwestern University, 303 East Superior, Chicago, IL 60611, USA
- International Institute for Nanotechnology, Northwestern University, 2145 Sheridan Road, Evanston, IL 60208, USA
| | - Lisa A. Hurley
- Ken and Ruth Davee Department of Neurology, The Northwestern Brain Tumor Institute, The Robert H. Lurie Comprehensive Cancer Center, Northwestern University, 303 East Superior, Chicago, IL 60611, USA
- International Institute for Nanotechnology, Northwestern University, 2145 Sheridan Road, Evanston, IL 60208, USA
| | - Juan Liu
- Department of Pharmacology and Cancer Biology, Duke University School of Medicine, Durham, NC 27710, USA
| | - Serena Tommasini-Ghelfi
- Ken and Ruth Davee Department of Neurology, The Northwestern Brain Tumor Institute, The Robert H. Lurie Comprehensive Cancer Center, Northwestern University, 303 East Superior, Chicago, IL 60611, USA
- International Institute for Nanotechnology, Northwestern University, 2145 Sheridan Road, Evanston, IL 60208, USA
| | - Yanrong Ji
- Preventive Medicine, Health and Biomedical Informatics, Feinberg School of Medicine, The Robert H. Lurie Comprehensive Cancer Center, Northwestern University, Chicago, IL 60611, USA
| | - Peng Gao
- Metabolomics Core Facility of Robert H. Lurie Comprehensive Cancer Center, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
| | - Andrea E. Calvert
- Ken and Ruth Davee Department of Neurology, The Northwestern Brain Tumor Institute, The Robert H. Lurie Comprehensive Cancer Center, Northwestern University, 303 East Superior, Chicago, IL 60611, USA
- International Institute for Nanotechnology, Northwestern University, 2145 Sheridan Road, Evanston, IL 60208, USA
| | - Andrew Lee
- Department of Chemical and Biological Engineering, Northwestern University, Evanston, IL 60208, USA
| | - Navdeep S. Chandel
- Department of Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL 60615, USA
| | - Ramana V. Davuluri
- Preventive Medicine, Health and Biomedical Informatics, Feinberg School of Medicine, The Robert H. Lurie Comprehensive Cancer Center, Northwestern University, Chicago, IL 60611, USA
| | - Craig M. Horbinski
- Department of Neurological Surgery, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
- Department of Pathology, Northwestern University Feinberg School of Medicine, Chicago, IL 60615, USA
| | - Jason W. Locasale
- Department of Pharmacology and Cancer Biology, Duke University School of Medicine, Durham, NC 27710, USA
| | - Alexander H. Stegh
- Ken and Ruth Davee Department of Neurology, The Northwestern Brain Tumor Institute, The Robert H. Lurie Comprehensive Cancer Center, Northwestern University, 303 East Superior, Chicago, IL 60611, USA
- International Institute for Nanotechnology, Northwestern University, 2145 Sheridan Road, Evanston, IL 60208, USA
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5
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Calvert AE, Chalastanis A, Wu Y, Hurley LA, Kouri FM, Bi Y, Kachman M, May JL, Bartom E, Hua Y, Mishra RK, Schiltz GE, Dubrovskyi O, Mazar AP, Peter ME, Zheng H, James CD, Burant CF, Chandel NS, Davuluri RV, Horbinski C, Stegh AH. Cancer-Associated IDH1 Promotes Growth and Resistance to Targeted Therapies in the Absence of Mutation. Cell Rep 2018; 19:1858-1873. [PMID: 28564604 DOI: 10.1016/j.celrep.2017.05.014] [Citation(s) in RCA: 137] [Impact Index Per Article: 22.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2016] [Revised: 03/22/2017] [Accepted: 05/02/2017] [Indexed: 12/13/2022] Open
Abstract
Oncogenic mutations in two isocitrate dehydrogenase (IDH)-encoding genes (IDH1 and IDH2) have been identified in acute myelogenous leukemia, low-grade glioma, and secondary glioblastoma (GBM). Our in silico and wet-bench analyses indicate that non-mutated IDH1 mRNA and protein are commonly overexpressed in primary GBMs. We show that genetic and pharmacologic inactivation of IDH1 decreases GBM cell growth, promotes a more differentiated tumor cell state, increases apoptosis in response to targeted therapies, and prolongs the survival of animal subjects bearing patient-derived xenografts (PDXs). On a molecular level, diminished IDH1 activity results in reduced α-ketoglutarate (αKG) and NADPH production, paralleled by deficient carbon flux from glucose or acetate into lipids, exhaustion of reduced glutathione, increased levels of reactive oxygen species (ROS), and enhanced histone methylation and differentiation marker expression. These findings suggest that IDH1 upregulation represents a common metabolic adaptation by GBMs to support macromolecular synthesis, aggressive growth, and therapy resistance.
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Affiliation(s)
- Andrea E Calvert
- Ken and Ruth Davee Department of Neurology, The Northwestern Brain Tumor Institute, The Robert H. Lurie Comprehensive Cancer Center, Feinberg School of Medicine, International Institute for Nanotechnology, Northwestern University, Chicago, IL 60611, USA
| | - Alexandra Chalastanis
- Ken and Ruth Davee Department of Neurology, The Northwestern Brain Tumor Institute, The Robert H. Lurie Comprehensive Cancer Center, Feinberg School of Medicine, International Institute for Nanotechnology, Northwestern University, Chicago, IL 60611, USA
| | - Yongfei Wu
- Ken and Ruth Davee Department of Neurology, The Northwestern Brain Tumor Institute, The Robert H. Lurie Comprehensive Cancer Center, Feinberg School of Medicine, International Institute for Nanotechnology, Northwestern University, Chicago, IL 60611, USA
| | - Lisa A Hurley
- Ken and Ruth Davee Department of Neurology, The Northwestern Brain Tumor Institute, The Robert H. Lurie Comprehensive Cancer Center, Feinberg School of Medicine, International Institute for Nanotechnology, Northwestern University, Chicago, IL 60611, USA
| | - Fotini M Kouri
- Ken and Ruth Davee Department of Neurology, The Northwestern Brain Tumor Institute, The Robert H. Lurie Comprehensive Cancer Center, Feinberg School of Medicine, International Institute for Nanotechnology, Northwestern University, Chicago, IL 60611, USA
| | - Yingtao Bi
- Division of Health and Biomedical Informatics, Department of Preventive Medicine, The Robert H. Lurie Comprehensive Cancer Center, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
| | - Maureen Kachman
- Michigan Regional Comprehensive Metabolomics Resource Core, University of Michigan, Ann Arbor, MI 48105, USA
| | - Jasmine L May
- Ken and Ruth Davee Department of Neurology, The Northwestern Brain Tumor Institute, The Robert H. Lurie Comprehensive Cancer Center, Feinberg School of Medicine, International Institute for Nanotechnology, Northwestern University, Chicago, IL 60611, USA
| | - Elizabeth Bartom
- Department of Biochemistry and Molecular Genetics, Robert H. Lurie Comprehensive Cancer Center, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
| | - Youjia Hua
- Division of Hematology/Oncology, The Robert H. Lurie Comprehensive Cancer Center, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
| | - Rama K Mishra
- Center for Molecular Innovation and Drug Discovery, Northwestern University, Evanston, IL 60208, USA
| | - Gary E Schiltz
- Center for Molecular Innovation and Drug Discovery, Northwestern University, Evanston, IL 60208, USA; Department of Pharmacology, Robert H. Lurie Comprehensive Cancer Center, Northwestern University, Chicago, IL 60611, USA
| | - Oleksii Dubrovskyi
- Chemistry of Life Processes Institute, Northwestern University, Evanston, IL 60208, USA
| | - Andrew P Mazar
- Chemistry of Life Processes Institute, Northwestern University, Evanston, IL 60208, USA
| | - Marcus E Peter
- Division of Hematology/Oncology, The Robert H. Lurie Comprehensive Cancer Center, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
| | - Hongwu Zheng
- Cold Spring Harbor Laboratories, Cold Spring Harbor, NY 11724, USA
| | - C David James
- Department of Neurological Surgery, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
| | - Charles F Burant
- Michigan Regional Comprehensive Metabolomics Resource Core, University of Michigan, Ann Arbor, MI 48105, USA
| | - Navdeep S Chandel
- Department of Medicine, Feinberg School of Medicine, Northwestern University, Chicago, IL 60615, USA
| | - Ramana V Davuluri
- Division of Health and Biomedical Informatics, Department of Preventive Medicine, The Robert H. Lurie Comprehensive Cancer Center, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
| | - Craig Horbinski
- Department of Neurological Surgery, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA; Department of Pathology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60615, USA
| | - Alexander H Stegh
- Ken and Ruth Davee Department of Neurology, The Northwestern Brain Tumor Institute, The Robert H. Lurie Comprehensive Cancer Center, Feinberg School of Medicine, International Institute for Nanotechnology, Northwestern University, Chicago, IL 60611, USA.
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Erogbogbo F, Liu X, May JL, Narain A, Gladding P, Swihart MT, Prasad PN. Plasmonic gold and luminescent silicon nanoplatforms for multimode imaging of cancer cells. Integr Biol (Camb) 2012; 5:144-50. [DOI: 10.1039/c2ib20100c] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Affiliation(s)
- Folarin Erogbogbo
- Department of Chemical and Biological Engineering, 303 Furnas Hall, The University at Buffalo, State University of New York, Buffalo, New York, 14260-4200, USA. Fax: +1 716-645-3822; Tel: +1 716-645-1181
| | - Xin Liu
- Department of Chemical and Biological Engineering, 303 Furnas Hall, The University at Buffalo, State University of New York, Buffalo, New York, 14260-4200, USA. Fax: +1 716-645-3822; Tel: +1 716-645-1181
| | - Jasmine L. May
- Institute for Lasers Photonics and Biophotonics, 458 Natural Sciences Complex, The University at Buffalo, State University of New York Buffalo, New York, 14260-4200, USA. Fax: +1 716-645-6945; Tel: +1 716-645-4162
| | - Ashley Narain
- Institute for Lasers Photonics and Biophotonics, 458 Natural Sciences Complex, The University at Buffalo, State University of New York Buffalo, New York, 14260-4200, USA. Fax: +1 716-645-6945; Tel: +1 716-645-4162
| | - Patrick Gladding
- North Shore Hospital, 142 Shakespeare Road, Westlake 0622, New Zealand
| | - Mark T. Swihart
- Department of Chemical and Biological Engineering, 303 Furnas Hall, The University at Buffalo, State University of New York, Buffalo, New York, 14260-4200, USA. Fax: +1 716-645-3822; Tel: +1 716-645-1181
| | - Paras N. Prasad
- Institute for Lasers Photonics and Biophotonics, 458 Natural Sciences Complex, The University at Buffalo, State University of New York Buffalo, New York, 14260-4200, USA. Fax: +1 716-645-6945; Tel: +1 716-645-4162
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Erogbogbo F, Chang CW, May JL, Liu L, Kumar R, Law WC, Ding H, Yong KT, Roy I, Sheshadri M, Swihart MT, Prasad PN. Bioconjugation of luminescent silicon quantum dots to gadolinium ions for bioimaging applications. Nanoscale 2012; 4:5483-5489. [PMID: 22854899 DOI: 10.1039/c2nr31002c] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Luminescent imaging agents and MRI contrast agents are desirable components in the rational design of multifunctional nanoconstructs for biological imaging applications. Luminescent biocompatible silicon quantum dots (SiQDs) and gadolinium chelates can be applied for fluorescence microscopy and MRI, respectively. Here, we report the first synthesis of a nanocomplex incorporating SiQDs and gadolinium ions (Gd³⁺) for biological applications. The nanoconstruct is composed of a PEGylated micelle, with hydrophobic SiQDs in its core, covalently bound to DOTA-chelated Gd³⁺. Dynamic light scattering reveals a radius of 85 nm for these nanoconstructs, which is consistent with the electron microscopy results depicting radii ranging from 25 to 60 nm. Cellular uptake of the probes verified that they maintain their optical properties within the intracellular environment. The magnetic resonance relaxivity of the nanoconstruct was 2.4 mM⁻¹ s⁻¹ (in terms of Gd³⁺ concentration), calculated to be around 6000 mM⁻¹ s⁻¹ per nanoconstruct. These desirable optical and relaxivity properties of the newly developed probe open the door for use of SiQDs in future multimodal applications such as tumour imaging.
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Affiliation(s)
- Folarin Erogbogbo
- Institute for Lasers Photonics and Biophotonics, 458 Natural Sciences Complex, The University at Buffalo, The State University of New York, Buffalo, New York 14260-3000, USA
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Clemons WM, Brodersen DE, McCutcheon JP, May JL, Carter AP, Morgan-Warren RJ, Wimberly BT, Ramakrishnan V. Crystal structure of the 30 S ribosomal subunit from Thermus thermophilus: purification, crystallization and structure determination. J Mol Biol 2001; 310:827-43. [PMID: 11453691 DOI: 10.1006/jmbi.2001.4778] [Citation(s) in RCA: 106] [Impact Index Per Article: 4.6] [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: 11/22/2022]
Abstract
We describe the crystallization and structure determination of the 30 S ribosomal subunit from Thermus thermophilus. Previous reports of crystals that diffracted to 10 A resolution were used as a starting point to improve the quality of the diffraction. Eventually, ideas such as the addition of substrates or factors to eliminate conformational heterogeneity proved less important than attention to detail in yielding crystals that diffracted beyond 3 A resolution. Despite improvements in technology and methodology in the last decade, the structure determination of the 30 S subunit presented some very challenging technical problems because of the size of the asymmetric unit, crystal variability and sensitivity to radiation damage. Some steps that were useful for determination of the atomic structure were: the use of anomalous scattering from the LIII edges of osmium and lutetium to obtain the necessary phasing signal; the use of tunable, third-generation synchrotron sources to obtain data of reasonable quality at high resolution; collection of derivative data precisely about a mirror plane to preserve small anomalous differences between Bijvoet mates despite extensive radiation damage and multi-crystal scaling; the pre-screening of crystals to ensure quality, isomorphism and the efficient use of scarce third-generation synchrotron time; pre-incubation of crystals in cobalt hexaammine to ensure isomorphism with other derivatives; and finally, the placement of proteins whose structures had been previously solved in isolation, in conjunction with biochemical data on protein-RNA interactions, to map out the architecture of the 30 S subunit prior to the construction of a detailed atomic-resolution model.
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Affiliation(s)
- W M Clemons
- MRC Laboratory of Molecular Biology, Hills Road, Cambridge, CB2 2QH, UK
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Abstract
The 30S ribosomal subunit binds messenger RNA and the anticodon stem-loop of transfer RNA during protein synthesis. A crystallographic analysis of the structure of the subunit from the bacterium Thermus thermophilus is presented. At a resolution of 5.5 A, the phosphate backbone of the ribosomal RNA is visible, as are the alpha-helices of the ribosomal proteins, enabling double-helical regions of RNA to be identified throughout the subunit, all seven of the small-subunit proteins of known crystal structure to be positioned in the electron density map, and the fold of the entire central domain of the small-subunit ribosomal RNA to be determined.
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Affiliation(s)
- W M Clemons
- Department of Biochemistry, University of Utah School of Medicine, Salt Lake City 84103, USA
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Abstract
Sperry and his colleagues had shown that section of the corpus callosum blocks the normally strong interocular transfer of visual learning in chiasma sectioned monkeys. Although interhemispheric transfer of learning was blocked, monkeys could be readily trained to use any combination of eye and hand in a task that required rapid visually guided responses. Sperry suggested that there must be a subcortical pathway linking sensory to motor areas of the brain. We tested monkeys in a task which required them to orient their wrist and fingers correctly in order to remove a morsel of food from a slotted disc. Animals in which we made lesions of the dorsal extrastriate visual areas of the parietal lobe were profoundly impaired in performing this task, but showed no deficit in visual discrimination learning. A monkey with an extensive lesion of the ventral, temporal lobe extrastriate areas showed no deficit in the visuomotor task but was profoundly impaired in visual discrimination learning. Lesions of peri-arcuate cortex, a major cortical target of parietal lobe visual areas, produced only a mild deficit which was motor in character. We suggest that the visuomotor deficit caused by parietal lobe lesions is brought about by depriving the cerebellum of its cortical visual input.
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Affiliation(s)
- M Glickstein
- Department of Anatomy, University of College London, UK
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Abstract
The increasing incidence of resistance to the antifungal agent, fluconazole, prompted the need for a rapid, reliable and easy-to-use susceptibility test. We have developed a disc diffusion test for fluconazole against Candida spp. suitable for a clinical laboratory. Disc diffusion tests on six different media were compared with MIC values. On the basis of correlation coefficient with MICs (r = -0.95), quality of growth and zone edge definition, Yeast Nitrogen Base agar with glucose (YNBG) produced the best results. Further studies on YNBG showed that the method is reliable for Candida albicans and for resistant isolates with no zone of inhibition, but results for the slower growing and uncommon species must be interpreted with some caution. Implementation of this test in the clinical laboratory has provided a much needed therapeutic service for clinicians within the hospital. It has also reduced the reliance on the reference laboratory for susceptibility results and the consequent costs involved.
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Affiliation(s)
- J L May
- Department of Microbiology, UMDS, London, UK
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12
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May JL. Modified median episiotomy minimizes the risk of third-degree tears. Obstet Gynecol 1994; 83:156-7. [PMID: 8272298] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
The standard median episiotomy can be easily modified by adding two half-inch transverse cuts in opposite directions in the perineal fascia just above the anal sphincter. The use of this new technique, which is referred to as a modified median episiotomy, increases the diameter at the vaginal outlet 83% more than that provided by a median episiotomy alone. The increased diameter is also 10% greater than a mediolateral episiotomy alone. When an episiotomy is indicated, the exclusive use of this procedure makes the occurrence of third-degree tears extremely rare. The episiotomy is easy to repair.
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Affiliation(s)
- J L May
- Department of Obstetrics and Gynecology, University of Texas Southwestern Medical Center at Dallas, Dallas
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Viteri AL, Howard PH, May JL, Ramesh GS, Roberts JW. Hepatic abscess due to Yersinia enterocolitica without bacteremia. Gastroenterology 1981; 81:592-3. [PMID: 7250646] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/02/2022]
Abstract
A 71-yr-old diabetic patient was evaluated because of right upper quadrant pain. He was found to have a large hepatic abscess secondary to Yersinia enterocolitica infection. He lacked clinical evidence of bacteremia or gastrointestinal infection. It is postulated that Yersinia enterocolitica reached the liver through the portal system from an inapparent intestinal infection. This is the first reported case of a liver abscess secondary to Yersinia enterocolitica without evidence of systemic infection.
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May JL, Swyngedauw J. [Toxic adenomas]. Lille Med 1972; 17:1573-4. [PMID: 4669611] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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