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van Wijk MH, Davies AG, Sterken MG, Mathies LD, Quamme EC, Blackwell GG, Riksen JAG, Kammenga JE, Bettinger JC. Natural allelic variation modifies acute ethanol response phenotypes in wild strains of C. elegans. Alcohol Clin Exp Res (Hoboken) 2023; 47:1505-1517. [PMID: 37356915 DOI: 10.1111/acer.15139] [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] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/03/2023] [Revised: 06/12/2023] [Accepted: 06/20/2023] [Indexed: 06/27/2023]
Abstract
BACKGROUND Genetic variation contributes to the likelihood that an individual will develop an alcohol use disorder (AUD). Traditional laboratory studies in animal models have elucidated the molecular pharmacology of ethanol, but laboratory-derived genetic manipulations rarely model the naturally occurring genetic variation observed in wild populations. Rather, these manipulations are biased toward identifying genes of central importance in the phenotypes. Because changes in such genes can confer selective disadvantages, they are not ideal candidates for carrying AUD risk alleles in humans. We sought to exploit Caenorhabditis elegans to identify allelic variation existing in the wild that modulates ethanol response behaviors. METHODS We tested the acute ethanol responses of four strains recently isolated from the wild (JU1511, JU1926, JU1931, and JU1941) and 41 multiparental recombinant inbred lines (mpRILs) derived from them. We assessed locomotion at 10, 30, and 50 min on low and high ethanol concentrations. We performed principal component analyses (PCA) on the different phenotypes, tested for transgressive behavior, calculated heritability, and determined the correlations between behavioral responses. RESULTS We observed a range of responses to ethanol across the strains. We detected a low-concentration locomotor activation effect in some of the mpRILs not seen in the laboratory wild-type strain. PCA showed different ethanol response behaviors to be independent. We observed transgressive behavior for many of the measured phenotypes and found that multiple behaviors were uncorrelated. The average broad-sense heritability for all phenotypes was 23.2%. CONCLUSIONS Genetic variation significantly affects multiple acute ethanol response behaviors, many of which are independent of one another. This suggests that the genetic variation captured by these strains likely affects multiple biological mechanisms through which ethanol acts. Further study of these strains may allow these distinct mechanisms to be identified.
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Affiliation(s)
- Marijke H van Wijk
- Laboratory of Nematology, Wageningen University & Research, Wageningen, The Netherlands
| | - Andrew G Davies
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, Virginia, USA
| | - Mark G Sterken
- Laboratory of Nematology, Wageningen University & Research, Wageningen, The Netherlands
| | - Laura D Mathies
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, Virginia, USA
| | - Elizabeth C Quamme
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, Virginia, USA
| | - GinaMari G Blackwell
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, Virginia, USA
| | - Joost A G Riksen
- Laboratory of Nematology, Wageningen University & Research, Wageningen, The Netherlands
| | - Jan E Kammenga
- Laboratory of Nematology, Wageningen University & Research, Wageningen, The Netherlands
| | - Jill C Bettinger
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, Virginia, USA
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Davies AG, Spandorfer M. An uncommon disease born from a common habit: pulmonary Langerhans cell histiocytosis. Am J Med Sci 2023. [DOI: 10.1016/s0002-9629(23)00618-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
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Gentry AE, Alexander JC, Ahangari M, Peterson RE, Miles MF, Bettinger JC, Davies AG, Groteweil M, Bacanu SA, Kendler KS, Riley BP, Webb BT. Case-only exome variation analysis of severe alcohol dependence using a multivariate hierarchical gene clustering approach. PLoS One 2023; 18:e0283985. [PMID: 37098020 PMCID: PMC10128939 DOI: 10.1371/journal.pone.0283985] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2022] [Accepted: 03/21/2023] [Indexed: 04/26/2023] Open
Abstract
BACKGROUND Variation in genes involved in ethanol metabolism has been shown to influence risk for alcohol dependence (AD) including protective loss of function alleles in ethanol metabolizing genes. We therefore hypothesized that people with severe AD would exhibit different patterns of rare functional variation in genes with strong prior evidence for influencing ethanol metabolism and response when compared to genes not meeting these criteria. OBJECTIVE Leverage a novel case only design and Whole Exome Sequencing (WES) of severe AD cases from the island of Ireland to quantify differences in functional variation between genes associated with ethanol metabolism and/or response and their matched control genes. METHODS First, three sets of ethanol related genes were identified including those a) involved in alcohol metabolism in humans b) showing altered expression in mouse brain after alcohol exposure, and altering ethanol behavioral responses in invertebrate models. These genes of interest (GOI) sets were matched to control gene sets using multivariate hierarchical clustering of gene-level summary features from gnomAD. Using WES data from 190 individuals with severe AD, GOI were compared to matched control genes using logistic regression to detect aggregate differences in abundance of loss of function, missense, and synonymous variants, respectively. RESULTS Three non-independent sets of 10, 117, and 359 genes were queried against control gene sets of 139, 1522, and 3360 matched genes, respectively. Significant differences were not detected in the number of functional variants in the primary set of ethanol-metabolizing genes. In both the mouse expression and invertebrate sets, we observed an increased number of synonymous variants in GOI over matched control genes. Post-hoc simulations showed the estimated effects sizes observed are unlikely to be under-estimated. CONCLUSION The proposed method demonstrates a computationally viable and statistically appropriate approach for genetic analysis of case-only data for hypothesized gene sets supported by empirical evidence.
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Affiliation(s)
- Amanda Elswick Gentry
- Virginia Institute for Psychiatric and Behavioral Genetics, Virginia Commonwealth University, Richmond, Virginia, United States of America
- Department of Psychiatry, Virginia Commonwealth University, Richmond, Virginia, United States of America
| | - Jeffry C Alexander
- Virginia Institute for Psychiatric and Behavioral Genetics, Virginia Commonwealth University, Richmond, Virginia, United States of America
| | - Mohammad Ahangari
- Virginia Institute for Psychiatric and Behavioral Genetics, Virginia Commonwealth University, Richmond, Virginia, United States of America
- Integrative Life Sciences Ph.D. Program, Virginia Commonwealth University, Richmond, Virginia, United States of America
| | - Roseann E Peterson
- Virginia Institute for Psychiatric and Behavioral Genetics, Virginia Commonwealth University, Richmond, Virginia, United States of America
- Department of Psychiatry, Virginia Commonwealth University, Richmond, Virginia, United States of America
- Department of Psychiatry and Behavioral Sciences, Institute for Genomics in Health, SUNY Downstate Health Sciences University, Brooklyn, New York, United States of America
- VCU Alcohol Research Center, Virginia Commonwealth University, Richmond, Virginia, United States of America
| | - Michael F Miles
- VCU Alcohol Research Center, Virginia Commonwealth University, Richmond, Virginia, United States of America
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, Virginia, United States of America
| | - Jill C Bettinger
- VCU Alcohol Research Center, Virginia Commonwealth University, Richmond, Virginia, United States of America
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, Virginia, United States of America
| | - Andrew G Davies
- VCU Alcohol Research Center, Virginia Commonwealth University, Richmond, Virginia, United States of America
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, Virginia, United States of America
| | - Mike Groteweil
- VCU Alcohol Research Center, Virginia Commonwealth University, Richmond, Virginia, United States of America
- Department of Human and Molecular Genetics, Virginia Commonwealth University, Richmond, Virginia, United States of America
| | - Silviu A Bacanu
- Virginia Institute for Psychiatric and Behavioral Genetics, Virginia Commonwealth University, Richmond, Virginia, United States of America
- Department of Psychiatry, Virginia Commonwealth University, Richmond, Virginia, United States of America
- VCU Alcohol Research Center, Virginia Commonwealth University, Richmond, Virginia, United States of America
| | - Kenneth S Kendler
- Virginia Institute for Psychiatric and Behavioral Genetics, Virginia Commonwealth University, Richmond, Virginia, United States of America
- Department of Psychiatry, Virginia Commonwealth University, Richmond, Virginia, United States of America
- VCU Alcohol Research Center, Virginia Commonwealth University, Richmond, Virginia, United States of America
| | - Brien P Riley
- Virginia Institute for Psychiatric and Behavioral Genetics, Virginia Commonwealth University, Richmond, Virginia, United States of America
- Department of Psychiatry, Virginia Commonwealth University, Richmond, Virginia, United States of America
- VCU Alcohol Research Center, Virginia Commonwealth University, Richmond, Virginia, United States of America
- Department of Human and Molecular Genetics, Virginia Commonwealth University, Richmond, Virginia, United States of America
| | - Bradley T Webb
- VCU Alcohol Research Center, Virginia Commonwealth University, Richmond, Virginia, United States of America
- GenOmics, Bioinformatics, and Translational Research Center, Biostatistics and Epidemiology Division, RTI International, Research Triangle Park, North Caroline, United States of America
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Vaughan M, Michailow W, Salih M, Li L, Beere H, Ritchie DA, Linfield EH, Davies AG, Cunningham JE. Directed delivery of terahertz frequency radiation from quantum cascade lasers within a dry 3He dilution refrigerator. Rev Sci Instrum 2022; 93:113906. [PMID: 36461439 DOI: 10.1063/5.0102553] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/10/2022] [Accepted: 10/08/2022] [Indexed: 06/17/2023]
Abstract
We present a scheme for the full integration of terahertz (THz) frequency quantum cascade lasers (QCLs) within a dilution refrigerator in order to provide a directed delivery of THz power into the sample space. We describe a successful operation of a 2.68 THz QCL located on the pulse tube cooler stage of the refrigerator, with its output coupled onto a two-dimensional electron gas (2DEG) located on a milli-kelvin sample stage via hollow metal waveguides and Hysol thermal isolators, achieving a total loss from QCL to the sample of ∼-9 dB. The thermal isolators limit heat leaks to the sample space, with a base temperature of ∼210 mK being achieved. We observe cyclotron resonance (CR) induced in the 2DEG by the QCL and explore the heating impact of the QCL on all stages of the refrigerator. The CR effect induced by the THz QCL is observable at electron temperatures as low as ∼430 mK. The results show a viable route for the exploitation of THz QCLs within the environment of a dilution refrigerator and for the THz power delivery in very low-temperature (<0.5 K) condensed matter experiments.
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Affiliation(s)
- M Vaughan
- School of Electronic and Electrical Engineering, University of Leeds, Leeds, West Yorkshire LS2 9JT, United Kingdom
| | - W Michailow
- Cavendish Laboratory, University of Cambridge, Cambridge, Cambridgeshire CB3 0HE, United Kingdom
| | - M Salih
- School of Electronic and Electrical Engineering, University of Leeds, Leeds, West Yorkshire LS2 9JT, United Kingdom
| | - L Li
- School of Electronic and Electrical Engineering, University of Leeds, Leeds, West Yorkshire LS2 9JT, United Kingdom
| | - H Beere
- Cavendish Laboratory, University of Cambridge, Cambridge, Cambridgeshire CB3 0HE, United Kingdom
| | - D A Ritchie
- Cavendish Laboratory, University of Cambridge, Cambridge, Cambridgeshire CB3 0HE, United Kingdom
| | - E H Linfield
- School of Electronic and Electrical Engineering, University of Leeds, Leeds, West Yorkshire LS2 9JT, United Kingdom
| | - A G Davies
- School of Electronic and Electrical Engineering, University of Leeds, Leeds, West Yorkshire LS2 9JT, United Kingdom
| | - J E Cunningham
- School of Electronic and Electrical Engineering, University of Leeds, Leeds, West Yorkshire LS2 9JT, United Kingdom
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Aliev F, Barr PB, Davies AG, Dick DM, Bettinger J. Genes regulating levels of ω-3 long-chain polyunsaturated fatty acids are associated with alcohol use disorder and consumption, and broader externalizing behavior in humans. Alcohol Clin Exp Res 2022; 46:1657-1664. [PMID: 35904282 PMCID: PMC9509483 DOI: 10.1111/acer.14916] [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] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2022] [Revised: 06/07/2022] [Accepted: 07/19/2022] [Indexed: 01/31/2023]
Abstract
BACKGROUND Individual variation in the physiological response to alcohol is predictive of an individual's likelihood to develop alcohol use disorder (AUD). Evidence from diverse model organisms indicates that the levels of long-chain polyunsaturated omega-3 fatty acids (ω-3 LC-PUFAs) can modulate the behavioral response to ethanol and therefore may impact the propensity to develop AUD. While most ω-3 LC-PUFAs come from diet, humans can produce these fatty acids from shorter chain precursors through a series of enzymatic steps. Natural variation in the genes encoding these enzymes has been shown to affect ω-3 LC-PUFA levels. We hypothesized that variation in these genes could contribute to the susceptibility to develop AUD. METHODS We identified nine genes (FADS1, FADS2, FADS3, ELOVL2, GCKR, ELOVL1, ACOX1, APOE, and PPARA) that are required to generate ω-3 LC-PUFAs and/or have been shown or predicted to affect ω-3 LC-PUFA levels. Using both set-based and gene-based analyses we examined their association with AUD and two AUD-related phenotypes, alcohol consumption, and an externalizing phenotype. RESULTS We found that the set of nine genes is associated with all three phenotypes. When examined individually, GCKR, FADS2, and ACOX1 showed significant association signals with alcohol consumption. GCKR was significantly associated with AUD. ELOVL1 and APOE were associated with externalizing. CONCLUSIONS Taken together with observations that dietary ω-3 LC-PUFAs can affect ethanol-related phenotypes, this work suggests that these fatty acids provide a link between the environmental and genetic influences on the risk of developing AUD.
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Affiliation(s)
- Fazil Aliev
- Department of PsychologyVirginia Commonwealth UniversityRichmondVirginiaUSA
| | - Peter B. Barr
- Department of PsychologyVirginia Commonwealth UniversityRichmondVirginiaUSA
- Department of Psychiatry & Behavioral SciencesSUNY Downstate Health Sciences UniversityBrooklynNew YorkUSA
| | - Andrew G. Davies
- Department of Pharmacology and ToxicologyVirginia Commonwealth UniversityRichmondVirginiaUSA
- Virginia Commonwealth University Alcohol Research CenterRichmondVirginiaUSA
| | - Danielle M. Dick
- Department of PsychologyVirginia Commonwealth UniversityRichmondVirginiaUSA
- Virginia Commonwealth University Alcohol Research CenterRichmondVirginiaUSA
| | - Jill C. Bettinger
- Department of Pharmacology and ToxicologyVirginia Commonwealth UniversityRichmondVirginiaUSA
- Virginia Commonwealth University Alcohol Research CenterRichmondVirginiaUSA
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Riepl J, Raab J, Abajyan P, Nong H, Freeman JR, Li LH, Linfield EH, Davies AG, Wacker A, Albes T, Jirauschek C, Lange C, Dhillon SS, Huber R. Field-resolved high-order sub-cycle nonlinearities in a terahertz semiconductor laser. Light Sci Appl 2021; 10:246. [PMID: 34924564 PMCID: PMC8685277 DOI: 10.1038/s41377-021-00685-5] [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] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/22/2021] [Revised: 11/18/2021] [Accepted: 11/23/2021] [Indexed: 06/14/2023]
Abstract
The exploitation of ultrafast electron dynamics in quantum cascade lasers (QCLs) holds enormous potential for intense, compact mode-locked terahertz (THz) sources, squeezed THz light, frequency mixers, and comb-based metrology systems. Yet the important sub-cycle dynamics have been notoriously difficult to access in operational THz QCLs. Here, we employ high-field THz pulses to perform the first ultrafast two-dimensional spectroscopy of a free-running THz QCL. Strong incoherent and coherent nonlinearities up to eight-wave mixing are detected below and above the laser threshold. These data not only reveal extremely short gain recovery times of 2 ps at the laser threshold, they also reflect the nonlinear polarization dynamics of the QCL laser transition for the first time, where we quantify the corresponding dephasing times between 0.9 and 1.5 ps with increasing bias currents. A density-matrix approach reproducing the emergence of all nonlinearities and their ultrafast evolution, simultaneously, allows us to map the coherently induced trajectory of the Bloch vector. The observed high-order multi-wave mixing nonlinearities benefit from resonant enhancement in the absence of absorption losses and bear potential for a number of future applications, ranging from efficient intracavity frequency conversion, mode proliferation to passive mode locking.
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Affiliation(s)
- J Riepl
- Department of Physics, University of Regensburg, Regensburg, Germany
| | - J Raab
- Department of Physics, University of Regensburg, Regensburg, Germany
| | - P Abajyan
- Laboratoire de Physique de l'Ecole Normale Supérieure, ENS, Université PSL, CNRS, Sorbonne Université, Université de Paris, Paris, France
| | - H Nong
- Laboratoire de Physique de l'Ecole Normale Supérieure, ENS, Université PSL, CNRS, Sorbonne Université, Université de Paris, Paris, France
| | - J R Freeman
- School of Electronic and Electrical Engineering, University of Leeds, Woodhouse Lane, Leeds, UK
| | - L H Li
- School of Electronic and Electrical Engineering, University of Leeds, Woodhouse Lane, Leeds, UK
| | - E H Linfield
- School of Electronic and Electrical Engineering, University of Leeds, Woodhouse Lane, Leeds, UK
| | - A G Davies
- School of Electronic and Electrical Engineering, University of Leeds, Woodhouse Lane, Leeds, UK
| | - A Wacker
- Mathematical Physics and NanoLund, Lund University, Lund, Sweden
| | - T Albes
- Department of Electrical and Computer Engineering, Technical University of Munich, Munich, Germany
| | - C Jirauschek
- Department of Electrical and Computer Engineering, Technical University of Munich, Munich, Germany
| | - C Lange
- Department of Physics, TU Dortmund University, Dortmund, Germany
| | - S S Dhillon
- Laboratoire de Physique de l'Ecole Normale Supérieure, ENS, Université PSL, CNRS, Sorbonne Université, Université de Paris, Paris, France.
| | - R Huber
- Department of Physics, University of Regensburg, Regensburg, Germany
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Stanyer EC, Baniqued PDE, Awais M, Kouara L, Davies AG, Killan EC, Mushtaq F. The impact of acoustic stimulation during sleep on memory and sleep architecture: A meta-analysis. J Sleep Res 2021; 31:e13385. [PMID: 34850995 DOI: 10.1111/jsr.13385] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [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: 10/21/2020] [Revised: 04/12/2021] [Accepted: 04/19/2021] [Indexed: 11/28/2022]
Abstract
The relationship between sleep and cognition has long been recognized, with slow-wave sleep thought to play a critical role in long-term memory consolidation. Recent research has presented the possibility that non-invasive acoustic stimulation during sleep could enhance memory consolidation. Herein, we report a random-effects model meta-analysis examining the impact of this intervention on memory and sleep architecture in healthy adults. Sixteen studies were identified through a systematic search. We found a medium significant effect of acoustic stimulation on memory task performance (g = 0.68, p = .031) in young adults <35 years of age, but no statistically significant effect in adults >35 years of age (g = -0.83, p = .223). In young adults, there was a large statistically significant effect for declarative memory tasks (g = 0.87, p = .014) but no effect for non-declarative tasks (g = -0.25, p = .357). There were no statistically significant differences in polysomnography-derived sleep architecture values between sham and stimulation conditions in either young or older adults. Based on these results, it appears that acoustic stimulation during sleep may only be an effective intervention for declarative memory consolidation in young adults. However, the small number of studies in this area, their small sample sizes, the short-term nature of most investigations and the high between-studies heterogeneity highlight a need for high-powered and long-term experiments to better elucidate, and subsequently maximise, any potential benefits of this novel approach.
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Affiliation(s)
- Emily C Stanyer
- School of Psychology, Faculty of Medicine and Health, University of Leeds, Leeds, West Yorkshire, UK.,Basic and Clinical Neuroscience, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK
| | - Paul Dominick E Baniqued
- School of Psychology, Faculty of Medicine and Health, University of Leeds, Leeds, West Yorkshire, UK.,School of Mechanical Engineering, Faculty of Engineering and Physical Sciences, University of Leeds, Leeds, West Yorkshire, UK
| | - Muhammad Awais
- School of Psychology, Faculty of Medicine and Health, University of Leeds, Leeds, West Yorkshire, UK.,Department of Computer Science, Edgehill University, Ormskirk, Lancashire, UK
| | - Layla Kouara
- School of Psychology, Faculty of Medicine and Health, University of Leeds, Leeds, West Yorkshire, UK
| | - Andrew G Davies
- Leeds Institute of Cardiovascular and Metabolic Medicine, Faculty of Medicine and Health, University of Leeds, Leeds, West Yorkshire, UK
| | - Edward C Killan
- Leeds Institute of Cardiovascular and Metabolic Medicine, Faculty of Medicine and Health, University of Leeds, Leeds, West Yorkshire, UK
| | - Faisal Mushtaq
- School of Psychology, Faculty of Medicine and Health, University of Leeds, Leeds, West Yorkshire, UK
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Sterken MG, van Wijk MH, Quamme EC, Riksen JAG, Carnell L, Mathies LD, Davies AG, Kammenga JE, Bettinger JC. Transcriptional analysis of the response of C. elegans to ethanol exposure. Sci Rep 2021; 11:10993. [PMID: 34040055 PMCID: PMC8155136 DOI: 10.1038/s41598-021-90282-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2020] [Accepted: 05/07/2021] [Indexed: 11/30/2022] Open
Abstract
Ethanol-induced transcriptional changes underlie important physiological responses to ethanol that are likely to contribute to the addictive properties of the drug. We examined the transcriptional responses of Caenorhabditis elegans across a timecourse of ethanol exposure, between 30 min and 8 h, to determine what genes and genetic pathways are regulated in response to ethanol in this model. We found that short exposures to ethanol (up to 2 h) induced expression of metabolic enzymes involved in metabolizing ethanol and retinol, while longer exposure (8 h) had much more profound effects on the transcriptome. Several genes that are known to be involved in the physiological response to ethanol, including direct ethanol targets, were regulated at 8 h of exposure. This longer exposure to ethanol also resulted in the regulation of genes involved in cilia function, which is consistent with an important role for the effects of ethanol on cilia in the deleterious effects of chronic ethanol consumption in humans. Finally, we found that food deprivation for an 8-h period induced gene expression changes that were somewhat ameliorated by the presence of ethanol, supporting previous observations that worms can use ethanol as a calorie source.
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Affiliation(s)
- Mark G Sterken
- Laboratory of Nematology, Wageningen University and Research, 6708 PB, Wageningen, The Netherlands
| | - Marijke H van Wijk
- Laboratory of Nematology, Wageningen University and Research, 6708 PB, Wageningen, The Netherlands
| | - Elizabeth C Quamme
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Box 980613, Richmond, VA, 23298, USA
| | - Joost A G Riksen
- Laboratory of Nematology, Wageningen University and Research, 6708 PB, Wageningen, The Netherlands
| | - Lucinda Carnell
- Department of Biological Sciences, Central Washington University, Ellensburg, WA, 98926, USA
| | - Laura D Mathies
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Box 980613, Richmond, VA, 23298, USA
- Virginia Commonwealth University Alcohol Research Center, Richmond, VA, USA
| | - Andrew G Davies
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Box 980613, Richmond, VA, 23298, USA
- Virginia Commonwealth University Alcohol Research Center, Richmond, VA, USA
| | - Jan E Kammenga
- Laboratory of Nematology, Wageningen University and Research, 6708 PB, Wageningen, The Netherlands
| | - Jill C Bettinger
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Box 980613, Richmond, VA, 23298, USA.
- Virginia Commonwealth University Alcohol Research Center, Richmond, VA, USA.
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Park SJ, Zonetti S, Parker-Jervis RS, Wu J, Wood CD, Li LH, Davies AG, Linfield EH, Sydoruk O, Cunningham JE. Terahertz magnetoplasmon resonances in coupled cavities formed in a gated two-dimensional electron gas. Opt Express 2021; 29:12958-12966. [PMID: 33985041 DOI: 10.1364/oe.414178] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/04/2020] [Accepted: 03/11/2021] [Indexed: 06/12/2023]
Abstract
We report on both experiments and theory of low-terahertz frequency range (up to 400 GHz) magnetoplasmons in a gated two-dimensional electron gas at low (<4K) temperatures. The evolution of magnetoplasmon resonances was observed as a function of magnetic field at frequencies up to ∼400 GHz. Full-wave 3D simulations of the system predicted the spatial distribution of plasmon modes in the 2D channel, along with their frequency response, allowing us to distinguish those resonances caused by bulk and edge magnetoplasmons in the experiments. Our methodology is anticipated to be applicable to the low temperature (<4K) on-chip terahertz measurements of a wide range of other low-dimensional mesoscopic systems.
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Mathies LD, Lindsay JH, Handal AP, Blackwell GG, Davies AG, Bettinger JC. SWI/SNF complexes act through CBP-1 histone acetyltransferase to regulate acute functional tolerance to alcohol. BMC Genomics 2020; 21:646. [PMID: 32957927 PMCID: PMC7507291 DOI: 10.1186/s12864-020-07059-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [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: 03/23/2020] [Accepted: 09/10/2020] [Indexed: 01/19/2023] Open
Abstract
Background SWI/SNF chromatin remodeling genes are required for normal acute responses to alcohol in C. elegans and are associated with alcohol use disorder in two human populations. In an effort to discover the downstream genes that are mediating this effect, we identified SWI/SNF-regulated genes in C. elegans. Results To identify SWI/SNF-regulated genes in adults, we compared mRNA expression in wild type and swsn-1(os22ts) worms under conditions that produce inactive swsn-1 in mature cells. To identify SWI/SNF-regulated genes in neurons, we compared gene expression in swsn-9(ok1354) null mutant worms that harbor a neuronal rescue or a control construct. RNA sequencing was performed to an average depth of 25 million reads per sample using 50-base, paired-end reads. We found that 6813 transcripts were significantly differentially expressed between swsn-1(os22ts) mutants and wild-type worms and 2412 transcripts were significantly differentially expressed between swsn-9(ok1354) mutants and swsn-9(ok1354) mutants with neuronal rescue. We examined the intersection between these two datasets and identified 603 genes that were differentially expressed in the same direction in both comparisons; we defined these as SWI/SNF-regulated genes in neurons and in adults. Among the differentially expressed genes was cbp-1, a C. elegans homolog of the mammalian CBP/p300 family of histone acetyltransferases. CBP has been implicated in the epigenetic regulation in response to alcohol in animal models and a polymorphism in the human CBP gene, CREBBP, has been associated with alcohol-related phenotypes. We found that cbp-1 is required for the development of acute functional tolerance to alcohol in C. elegans. Conclusions We identified 603 transcripts that were regulated by two different SWI/SNF complex subunits in adults and in neurons. The SWI/SNF-regulated genes were highly enriched for genes involved in membrane rafts, suggesting an important role for this membrane microdomain in the acute alcohol response. Among the differentially expressed genes was cbp-1; CBP-1 homologs have been implicated in alcohol responses across phyla and we found that C. elegans cbp-1 was required for the acute alcohol response in worms.
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Affiliation(s)
- Laura D Mathies
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, PO Box 980613, Richmond, VA, 23298, USA.
| | - Jonathan H Lindsay
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, PO Box 980613, Richmond, VA, 23298, USA
| | - Amal P Handal
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, PO Box 980613, Richmond, VA, 23298, USA
| | - GinaMari G Blackwell
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, PO Box 980613, Richmond, VA, 23298, USA
| | - Andrew G Davies
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, PO Box 980613, Richmond, VA, 23298, USA
| | - Jill C Bettinger
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, PO Box 980613, Richmond, VA, 23298, USA
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Bacon DR, Gill TB, Rosamond M, Burnett AD, Dunn A, Li L, Linfield EH, Davies AG, Dean P, Freeman JR. Photoconductive arrays on insulating substrates for high-field terahertz generation. Opt Express 2020; 28:17219-17231. [PMID: 32679934 DOI: 10.1364/oe.391656] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/02/2020] [Accepted: 05/01/2020] [Indexed: 06/11/2023]
Abstract
We report on the design, fabrication and characterisation of large-area photoconductive THz array structures, consisting of a thin LT-GaAs active region transferred to an insulating substrate using a wafer-scale bonding process. The electrically insulating, transparent substrate reduces the parasitic currents in the devices, allowing peak THz-fields as high as 120 kV cm-1 to be generated over a bandwidth >5 THz. These results are achieved using lower pulse energies than demanded by conventional photoconductive arrays and other popular methods of generating high-field THz radiation. Two device sizes are fully characterised and the emission properties are compared to generation by optical rectification in ZnTe. The device can be operated in an optically saturated regime in order to suppress laser noise.
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12
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Kundu I, Freeman JR, Dean P, Li LH, Linfield EH, Davies AG. Terahertz photonic integrated circuit for frequency tuning and power modulation. Opt Express 2020; 28:4374-4386. [PMID: 32121675 DOI: 10.1364/oe.380656] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/15/2019] [Accepted: 01/10/2020] [Indexed: 06/10/2023]
Abstract
The quantum cascade laser is a powerful solid-state source of terahertz-frequency radiation. However, integrating multiple photonic functions into a monolithic platform in this frequency range is non-trivial due to the scaling of photonic structures for the long terahertz wavelengths and the low frequency tuning coefficients of the quantum cascade lasers. Here, we have designed a simple terahertz-frequency photonic integrated circuit by coupling a racetrack resonator with a ridge laser in the longitudinal direction to design a notch filter. The transmission properties of this filter structure are dependent on the phase matching and losses in the coupled racetrack and results in a comb of stopband frequencies. We have optimized the comb separation by carefully selecting the cavity dimensions of the racetrack resonator to suppress longitudinal modes in the ridge laser enabling single-mode emission. The emission frequencies and output power from laser are controlled through appropriate control of drive currents to the ridge and the racetrack resonator. The emission frequency is electrically tuned over ∼81 GHz exploiting Stark shift of the gain as a function of drive current at the ridge laser, coinciding with an output power variation of ∼27% of the peak power (at a heat sink temperature of 50 K). The output power from the ridge also varied by ∼30% and the frequency was tuned by a further 10 GHz when the driving conditions at the ridge laser are invariant and the current at the racetrack resonator was varied. To our best knowledge, this is the first report of a frequency engineering, tuning and power modulation of terahertz-frequency quantum cascade lasers using a photonic integrated circuit.
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Edwards AC, Heron J, Hibbeln J, Schuckit MA, Webb BT, Hickman M, Davies AG, Bettinger JC. Long-Chain ω-3 Levels Are Associated With Increased Alcohol Sensitivity in a Population-Based Sample of Adolescents. Alcohol Clin Exp Res 2019; 43:2620-2626. [PMID: 31589770 PMCID: PMC6904498 DOI: 10.1111/acer.14212] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2019] [Accepted: 10/01/2019] [Indexed: 01/12/2023]
Abstract
BACKGROUND The levels of the ω-3 long-chain polyunsaturated fatty acids (ω-3 LC-PUFAs), including eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), have been associated with alcohol sensitivity in vertebrate and invertebrate model systems, but prior studies have not examined this association in human samples despite evidence of associations between ω-3 LC-PUFA levels and alcohol-related phenotypes. Both alcohol sensitivity and ω-3 LC-PUFA levels are impacted by genetic factors, and these influences may contribute to observed associations between phenotypes. Given the potential for using EPA and DHA supplementation in adjuvant care for alcohol misuse and other outcomes, it is important to clarify how ω-3 LC-PUFA levels relate to alcohol sensitivity. METHODS Analyses were conducted using data from the Avon Longitudinal Study of Parents and Children. Plasma ω-3 LC-PUFA levels were measured at ages 15.5 and 17.5. Participants reported on their initial alcohol sensitivity using the early drinking Self-Rating of the Effects of Alcohol (SRE-5) scale, for which more drinks needed for effects indicates lower levels of response per drink, at ages 15.5, 16.5, and 17.5. Polygenic liability for alcohol consumption, alcohol problems, EPA levels, and DHA levels was derived using summary statistics from large, publicly available datasets. Linear regressions were used to examine the cross-sectional and longitudinal associations between ω-3 LC-PUFA levels and SRE scores. RESULTS Age 15.5 ω-3 LC-PUFA levels were negatively associated with contemporaneous SRE scores and with age 17.5 SRE scores. One modest association (p = 0.02) between polygenic liability and SRE scores was observed, between alcohol problems-based polygenic risk scores (PRS) and age 16.5 SRE scores. Tests of moderation by genetic liability were not warranted. CONCLUSIONS Plasma ω-3 LC-PUFA levels may be related to initial sensitivity to alcohol during adolescence. These data indicate that diet-related factors have the potential to impact humans' earliest responses to alcohol exposure.
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Affiliation(s)
- Alexis C. Edwards
- Virginia Institute for Psychiatric and Behavioral Genetics, Department of Psychiatry, Virginia Commonwealth University, Richmond, VA, US
| | - Jon Heron
- Population Health Sciences, Bristol Medical School, University of Bristol, Bristol, UK
| | - Joseph Hibbeln
- Section on Nutritional Neurosciences, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Rockville, MD, US
| | - Marc A. Schuckit
- Department of Psychiatry, University of California, San Diego, La Jolla, CA, US
| | - Bradley T. Webb
- Virginia Institute for Psychiatric and Behavioral Genetics, Department of Psychiatry, Virginia Commonwealth University, Richmond, VA, US
| | - Matthew Hickman
- Population Health Sciences, Bristol Medical School, University of Bristol, Bristol, UK
| | - Andrew G. Davies
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, VA, US
| | - Jill C. Bettinger
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, VA, US
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Meng K, Park SJ, Li LH, Bacon DR, Chen L, Chae K, Park JY, Burnett AD, Linfield EH, Davies AG, Cunningham JE. Tunable broadband terahertz polarizer using graphene-metal hybrid metasurface. Opt Express 2019; 27:33768-33778. [PMID: 31878438 DOI: 10.1364/oe.27.033768] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/06/2019] [Accepted: 10/14/2019] [Indexed: 06/10/2023]
Abstract
We demonstrate an electrically tunable polarizer for terahertz (THz) frequency electromagnetic waves formed from a hybrid graphene-metal metasurface. Broadband (>3 THz) polarization-dependent modulation of THz transmission is demonstrated as a function of the graphene conductivity for various wire grid geometries, each tuned by gating using an overlaid ion gel. We show a strong enhancement of modulation (up to ∼17 times) compared to graphene wire grids in the frequency range of 0.2-2.5 THz upon introduction of the metallic elements. Theoretical calculations, considering both plasmonic coupling and Drude absorption, are in good agreement with our experimental findings.
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15
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Meng K, Park SJ, Burnett AD, Gill T, Wood CD, Rosamond M, Li LH, Chen L, Bacon DR, Freeman JR, Dean P, Ahn YH, Linfield EH, Davies AG, Cunningham JE. Increasing the sensitivity of terahertz split ring resonator metamaterials for dielectric sensing by localized substrate etching. Opt Express 2019; 27:23164-23172. [PMID: 31510599 DOI: 10.1364/oe.27.023164] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/16/2019] [Accepted: 06/11/2019] [Indexed: 05/18/2023]
Abstract
We demonstrate a significant enhancement in the sensitivity of split ring resonator terahertz metamaterial dielectric sensors by the introduction of etched trenches into their inductive-capacitive gap area, both through finite element simulations and in experiments performed using terahertz time-domain spectroscopy. The enhanced sensitivity is demonstrated by observation of an increased frequency shift in response to overlaid dielectric material of thicknesses up to 18 µm deposited on to the sensor surface. We show that sensitivity to the dielectric is enhanced by a factor of up to ∼2.7 times by the incorporation of locally etched trenches with a depth of ∼3.4 µm, for example, and discuss the effect of the etching on the electrical properties of the sensors. Our experimental findings are in good agreement with simulations of the sensors obtained using finite element methods.
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Keeley J, Bertling K, Rubino PL, Lim YL, Taimre T, Qi X, Kundu I, Li LH, Indjin D, Rakić AD, Linfield EH, Davies AG, Cunningham J, Dean P. Detection sensitivity of laser feedback interferometry using a terahertz quantum cascade laser. Opt Lett 2019; 44:3314-3317. [PMID: 31259948 DOI: 10.1364/ol.44.003314] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/20/2019] [Accepted: 05/08/2019] [Indexed: 06/09/2023]
Abstract
We report on the high detection sensitivity of a laser feedback interferometry scheme based on a terahertz frequency quantum cascade laser (QCL). We show that variations on the laser voltage induced by optical feedback to the laser can be resolved with the reinjection of powers as low as ∼-125 dB of the emitted power. Our measurements demonstrate a noise equivalent power of ∼1.4 pW/√Hz, although, after accounting for the reinjection losses, we estimate that this corresponds to only ∼1 fW/√Hz being coupled to the QCL active region.
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17
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Mathies LD, Ray S, Lopez-Alvillar K, Arbeitman MN, Davies AG, Bettinger JC. mRNA profiling reveals significant transcriptional differences between a multipotent progenitor and its differentiated sister. BMC Genomics 2019; 20:427. [PMID: 31138122 PMCID: PMC6540470 DOI: 10.1186/s12864-019-5821-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [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: 12/18/2018] [Accepted: 05/21/2019] [Indexed: 12/15/2022] Open
Abstract
Background The two Caenorhabditis elegans somatic gonadal precursors (SGPs) are multipotent progenitors that generate all somatic tissues of the adult reproductive system. The sister cells of the SGPs are two head mesodermal cells (hmcs); one hmc dies by programmed cell death and the other terminally differentiates. Thus, a single cell division gives rise to one multipotent progenitor and one differentiated cell with identical lineage histories. We compared the transcriptomes of SGPs and hmcs in order to learn the determinants of multipotency and differentiation in this lineage. Results We generated a strain that expressed fluorescent markers specifically in SGPs (ehn-3A::tdTomato) and hmcs (bgal-1::GFP). We dissociated cells from animals after the SGP/hmc cell division, but before the SGPs had further divided, and subjected the dissociated cells to fluorescence-activated cell sorting to collect isolated SGPs and hmcs. We analyzed the transcriptomes of these cells and found that 5912 transcripts were significantly differentially expressed, with at least two-fold change in expression, between the two cell types. The hmc-biased genes were enriched with those that are characteristic of neurons. The SGP-biased genes were enriched with those indicative of cell proliferation and development. We assessed the validity of our differentially expressed genes by examining existing reporters for five of the 10 genes with the most significantly biased expression in SGPs and found that two showed expression in SGPs. For one reporter that did not show expression in SGPs, we generated a GFP knock-in using CRISPR/Cas9. This reporter, in the native genomic context, was expressed in SGPs. Conclusions We found that the transcriptional profiles of SGPs and hmcs are strikingly different. The hmc-biased genes are enriched with those that encode synaptic transmission machinery, which strongly suggests that it has neuron-like signaling properties. In contrast, the SGP-biased genes are enriched with genes that encode factors involved in transcription and translation, as would be expected from a cell preparing to undergo proliferative divisions. Mediators of multipotency are likely to be among the genes differentially expressed in SGPs. Electronic supplementary material The online version of this article (10.1186/s12864-019-5821-z) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Laura D Mathies
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, PO Box 980613, Richmond, VA, 23298, USA.
| | - Surjyendu Ray
- Department of Biomedical Sciences, College of Medicine, Florida State University, Tallahassee, FL, 32306, USA
| | - Kayla Lopez-Alvillar
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, PO Box 980613, Richmond, VA, 23298, USA
| | - Michelle N Arbeitman
- Department of Biomedical Sciences, College of Medicine, Florida State University, Tallahassee, FL, 32306, USA
| | - Andrew G Davies
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, PO Box 980613, Richmond, VA, 23298, USA
| | - Jill C Bettinger
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, PO Box 980613, Richmond, VA, 23298, USA
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18
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Han YJ, Partington J, Chhantyal-Pun R, Henry M, Auriacombe O, Rawlings T, Li LH, Keeley J, Oldfield M, Brewster N, Dong R, Dean P, Davies AG, Ellison BN, Linfield EH, Valavanis A. Gas spectroscopy through multimode self-mixing in a double-metal terahertz quantum cascade laser. Opt Lett 2018; 43:5933-5936. [PMID: 30547973 DOI: 10.1364/ol.43.005933] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2018] [Accepted: 10/10/2018] [Indexed: 06/09/2023]
Abstract
A multimode self-mixing terahertz-frequency gas absorption spectroscopy is demonstrated based on a quantum cascade laser. A double-metal device configuration is used to expand the laser's frequency tuning range, and a precision-micromachined external waveguide module is used to enhance the optical feedback. Methanol spectra are measured using two laser modes at 3.362 and 3.428 THz, simultaneously, with more than eight absorption peaks resolved over a 17 GHz bandwidth, which provide the noise-equivalent absorption sensitivity of 1.20×10-3 cm-1 Hz-1/2 and 2.08×10-3 cm-1 Hz-1/2, respectively. In contrast to all previous self-mixing spectroscopy, our multimode technique expands the sensing bandwidth and duty cycle significantly.
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19
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Wolstenholme JT, Bowers MS, Pais AB, Pais AC, Poland RS, Poklis JL, Davies AG, Bettinger JC. Dietary Omega-3 Fatty Acids Differentially Impact Acute Ethanol-Responsive Behaviors and Ethanol Consumption in DBA/2J Versus C57BL/6J Mice. Alcohol Clin Exp Res 2018; 42:1476-1485. [PMID: 29786878 DOI: 10.1111/acer.13780] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [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: 02/15/2018] [Accepted: 05/15/2018] [Indexed: 11/27/2022]
Abstract
BACKGROUND Complex interactions between environmental and genetic factors influence the risk of developing alcohol use disorder (AUD) in humans. To date, studies of the impact of environment on AUD risk have primarily focused on psychological characteristics or on the effects of developmental exposure to ethanol (EtOH). We recently observed that modifying levels of the long-chain ω-3 (LC ω-3) fatty acid, eicosapentaenoic acid (EPA), alters acute physiological responses to EtOH in Caenorhabditis elegans. Because mammals derive ω-3 fatty acids from their diet, here we asked if manipulating dietary levels of LC ω-3 fatty acids can affect EtOH-responsive behaviors in mice. METHODS We used 2 well-characterized inbred mouse strains, C57BL/6J (B6) and DBA/2J (D2), which differ in their responses to EtOH. Age-matched young adult male mice were maintained on isocaloric diets that differed only by being enriched or depleted in LC ω-3 fatty acids. Animals were subsequently tested for acute EtOH sensitivity (locomotor activation and sedation), voluntary consumption, and metabolism. Fat deposition was also determined. RESULTS We found that dietary levels of LC ω-3s altered EtOH sensitivity and consumption in a genotype-specific manner. Both B6 and D2 animals fed high LC ω-3 diets demonstrated lower EtOH-induced locomotor stimulation than those fed low LC ω-3 diets. EtOH sedation and EtOH metabolism were greater in D2, but not B6 mice on the high LC ω-3 diet. Conversely, LC ω-3 dietary manipulation altered EtOH consumption in B6, but not in D2 mice. B6 mice on a high LC ω-3 diet consumed more EtOH in a 2-bottle choice intermittent access model than B6 mice on a low LC ω-3 diet. CONCLUSIONS Because EtOH sensitivity is predictive of risk of developing AUD in humans, our data indicate that dietary LC ω-3 levels should be evaluated for their impact on AUD risk in humans. Further, these studies indicate that genetic background can interact with fatty acids in the diet to significantly alter EtOH-responsive behaviors.
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Affiliation(s)
- Jennifer T Wolstenholme
- Department of Pharmacology and Toxicology , Virginia Commonwealth University, Richmond, Virginia.,VCU-Alcohol Research Center, Virginia Commonwealth University, Richmond, Virginia
| | - M Scott Bowers
- Department of Biomedical Engineering , Faulk Center for Molecular Therapeutics, Northwestern University, Chicago, Illinois
| | - Alexander B Pais
- VCU-Alcohol Research Center, Virginia Commonwealth University, Richmond, Virginia
| | - A Christian Pais
- VCU-Alcohol Research Center, Virginia Commonwealth University, Richmond, Virginia
| | - Ryan S Poland
- VCU-Alcohol Research Center, Virginia Commonwealth University, Richmond, Virginia
| | - Justin L Poklis
- Department of Pharmacology and Toxicology , Virginia Commonwealth University, Richmond, Virginia
| | - Andrew G Davies
- Department of Pharmacology and Toxicology , Virginia Commonwealth University, Richmond, Virginia.,VCU-Alcohol Research Center, Virginia Commonwealth University, Richmond, Virginia
| | - Jill C Bettinger
- Department of Pharmacology and Toxicology , Virginia Commonwealth University, Richmond, Virginia.,VCU-Alcohol Research Center, Virginia Commonwealth University, Richmond, Virginia
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20
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Han YJ, Li LH, Zhu J, Valavanis A, Freeman JR, Chen L, Rosamond M, Dean P, Davies AG, Linfield EH. Silver-based surface plasmon waveguide for terahertz quantum cascade lasers. Opt Express 2018; 26:3814-3827. [PMID: 29475360 DOI: 10.1364/oe.26.003814] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/20/2017] [Accepted: 12/18/2017] [Indexed: 06/08/2023]
Abstract
Terahertz-frequency quantum cascade lasers (THz QCLs) based on ridge waveguides incorporating silver waveguide layers have been investigated theoretically and experimentally, and compared with traditional gold-based devices. The threshold gain associated with silver-, gold- and copper-based devices, and the effects of titanium adhesion layers and top contact layers, in both surface-plasmon and double-metal waveguide geometries, have been analysed. Our simulations show that silver-based waveguides yield lower losses for THz QCLs across all practical operating temperatures and frequencies. Experimentally, QCLs with silver-based surface-plasmon waveguides were found to exhibit higher operating temperatures and higher output powers compared to those with identical but gold-based waveguides. Specifically, for a three-well resonant phonon active region with a scaled oscillator strength of 0.43 and doping density of 6.83 × 1015 cm-3, an increase of 5 K in the maximum operating temperature and 40% increase in the output power were demonstrated. These effects were found to be dependent on the active region design, and greater improvements were observed for QCLs with a larger radiative diagonality. Our results indicate that silver-based waveguide structures could potentially enable THz QCLs to operate at high temperatures.
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21
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Vijayan S, Barmby DS, Pearson IR, Davies AG, Wheatcroft SB, Sivananthan M. Assessing Coronary Blood Flow Physiology in the Cardiac Catheterisation Laboratory. Curr Cardiol Rev 2017; 13:232-243. [PMID: 28545351 PMCID: PMC5633718 DOI: 10.2174/1573403x13666170525102618] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/28/2017] [Revised: 05/09/2017] [Accepted: 05/17/2017] [Indexed: 01/10/2023] Open
Abstract
Background: Contemporary management of coronary disease focuses on the treatment of stenoses in the major epicardial vessels. However, myocardial blood flow is known to be contingent on a range of factors in addition to the patency of the epicardial vessels. These include anatomical and physiological factors such as the extent of myocardium supplied by the vessel, systemic blood pres-sure, the natural variation in vascular tone in response to physiological needs which allows for coro-nary autoregulation and pathological factors such as the presence of downstream obstruction to flow due to disease of the small coronary vessels or myocardium. The assessment of clinical effectiveness and adequacy of coronary revascularisation requires the ability to comprehensively and accurately as-sess and measure myocardial perfusion. Conclusion: In this article, we review the current methods of evaluating coronary blood flow and my-ocardial perfusion in the cardiac catheterisation laboratory.
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Affiliation(s)
- Sethumadhavan Vijayan
- Interventional Fellow, Department of Cardiology, Leeds General Infirmary, Great George Street, Leeds, LS1 3EX, United Kingdom
| | - David S Barmby
- Department of Cardiology, Sheffield Teaching Hospitals NHS Foundation Trust, Sheffield, United Kingdom
| | - Ian R Pearson
- Department of Cardiology, Leeds Teaching Hospitals NHS Trust, Leeds, United Kingdom
| | - Andrew G Davies
- Leeds Institute of Cardiovascular and Metabolic Medicine, University of Leeds, Leeds, United Kingdom
| | - Stephen B Wheatcroft
- Leeds Institute of Cardiovascular and Metabolic Medicine, University of Leeds, Leeds, United Kingdom
| | - Mohan Sivananthan
- Department of Cardiology, Leeds Teaching Hospitals NHS Trust, Leeds, United Kingdom
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22
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Mathies LD, Aliev F, Davies AG, Dick DM, Bettinger JC. Variation in SWI/SNF Chromatin Remodeling Complex Proteins is Associated with Alcohol Dependence and Antisocial Behavior in Human Populations. Alcohol Clin Exp Res 2017; 41:2033-2040. [PMID: 28981154 DOI: 10.1111/acer.13514] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [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: 04/28/2017] [Accepted: 09/28/2017] [Indexed: 01/21/2023]
Abstract
BACKGROUND Testing for direct gene or single nucleotide polymorphism replication of association across studies may not capture the true importance of a candidate locus; rather, we suggest that relevant replication across studies may be found at the level of a biological process. We previously observed that variation in 2 members of the switching defective/sucrose nonfermenting (SWI/SNF) chromatin remodeling complex is associated with alcohol dependence (AD) in the Irish Affected Sib Pair Study for Alcohol Dependence. Here, we tested for association with alcohol-related outcomes using a set of genes functioning in the SWI/SNF complex in 2 independent samples. METHODS We used a set-based analysis to examine the 29 genes of the SWI/SNF complex for evidence of association with (i) AD in the adult Collaborative Study on the Genetics of Alcoholism (COGA) case-control sample and (ii) antisocial behavior, hypothesized to be a genetically related developmental precursor, in a younger population sample (Spit for Science [S4S]). RESULTS We found evidence for association of the SWI/SNF complex with AD in COGA (p = 0.0435) and more general antisocial behavior in S4S (p = 0.00026). The genes that contributed most strongly to the signal in COGA were SS18L1, SMARCD1, BRD7, BCL7B, SMARCB1, and BCL11A. In the S4S sample, ACTB, ARID2, BCL11A, BCL11B, BCL7B, BCL7C, DPF2, and DPF3 all contributed strongly to the signal. CONCLUSIONS We detected associations between the SWI/SNF complex and AD in an adult population selected from treatment-seeking probands and antisocial behavior in an adolescent population sample. This provides strong support for a role for SWI/SNF in the development of alcohol-related problems.
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Affiliation(s)
- Laura D Mathies
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, Virginia
| | - Fazil Aliev
- Department of Psychology, Virginia Commonwealth University, Richmond, Virginia.,Karabuk University, Karabuk, Turkey
| | | | - Andrew G Davies
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, Virginia.,Virginia Commonwealth University Alcohol Research Center, Richmond, Virginia
| | - Danielle M Dick
- Department of Psychology, Virginia Commonwealth University, Richmond, Virginia.,Virginia Commonwealth University Alcohol Research Center, Richmond, Virginia.,Department of Human and Molecular Genetics, Virginia Commonwealth University, Richmond, Virginia
| | - Jill C Bettinger
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, Virginia.,Virginia Commonwealth University Alcohol Research Center, Richmond, Virginia
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de Kleer K, Skrutskie M, Leisenring J, Davies AG, Conrad A, de Pater I, Resnick A, Bailey V, Defrère D, Hinz P, Skemer A, Spalding E, Vaz A, Veillet C, Woodward CE. Multi-phase volcanic resurfacing at Loki Patera on Io. Nature 2017; 545:199-202. [PMID: 28492251 DOI: 10.1038/nature22339] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2016] [Accepted: 03/29/2017] [Indexed: 11/09/2022]
Abstract
The Jovian moon Io hosts the most powerful persistently active volcano in the Solar System, Loki Patera. The interior of this volcanic, caldera-like feature is composed of a warm, dark floor covering 21,500 square kilometres surrounding a much cooler central 'island'. The temperature gradient seen across areas of the patera indicates a systematic resurfacing process, which has been seen to occur typically every one to three years since the 1980s. Analysis of past data has indicated that the resurfacing progressed around the patera in an anti-clockwise direction at a rate of one to two kilometres per day, and that it is caused either by episodic eruptions that emplace voluminous lava flows or by a cyclically overturning lava lake contained within the patera. However, spacecraft and telescope observations have been unable to map the emission from the entire patera floor at sufficient spatial resolution to establish the physical processes at play. Here we report temperature and lava cooling age maps of the entire patera floor at a spatial sampling of about two kilometres, derived from ground-based interferometric imaging of thermal emission from Loki Patera obtained on 8 March 2015 ut as the limb of Europa occulted Io. Our results indicate that Loki Patera is resurfaced by a multi-phase process in which two waves propagate and converge around the central island. The different velocities and start times of the waves indicate a non-uniformity in the lava gas content and/or crust bulk density across the patera.
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Affiliation(s)
- K de Kleer
- Department of Astronomy, University of California at Berkeley, Berkeley, California, USA
| | - M Skrutskie
- Department of Astronomy, University of Virginia, Charlottesville, Virginia, USA
| | - J Leisenring
- Steward Observatory, University of Arizona, Tucson, Arizona, USA
| | - A G Davies
- Jet Propulsion Laboratory - California Institute of Technology, Pasadena, California, USA
| | - A Conrad
- The Large Binocular Telescope Observatory, University of Arizona, Tucson, Arizona, USA
| | - I de Pater
- Department of Astronomy, University of California at Berkeley, Berkeley, California, USA
| | - A Resnick
- Department of Physics and Astronomy, Amherst College, Amherst, Massachusetts, USA
| | - V Bailey
- Kavli Institute for Particle Astrophysics and Cosmology, Department of Physics, Stanford University, Palo Alto, California, USA
| | - D Defrère
- Space Sciences, Technologies and Astrophysics Research (STAR) Institute, University of Liège, Liège, Wallonia, Belgium
| | - P Hinz
- Steward Observatory, University of Arizona, Tucson, Arizona, USA
| | - A Skemer
- PBSci-Astronomy and Astrophysics Department, University of California at Santa Cruz, Santa Cruz, California, USA
| | - E Spalding
- Steward Observatory, University of Arizona, Tucson, Arizona, USA
| | - A Vaz
- Steward Observatory, University of Arizona, Tucson, Arizona, USA
| | - C Veillet
- The Large Binocular Telescope Observatory, University of Arizona, Tucson, Arizona, USA
| | - C E Woodward
- Minnesota Institute for Astrophysics, University of Minnesota, Minneapolis, Minnesota, USA
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Gislason-Lee AJ, Keeble C, Egleston D, Bexon J, Kengyelics SM, Davies AG. Comprehensive assessment of patient image quality and radiation dose in latest generation cardiac x-ray equipment for percutaneous coronary interventions. J Med Imaging (Bellingham) 2017; 4:025501. [PMID: 28491907 PMCID: PMC5412945 DOI: 10.1117/1.jmi.4.2.025501] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2016] [Accepted: 04/14/2017] [Indexed: 11/14/2022] Open
Abstract
This study aimed to determine whether a reduction in radiation dose was found for percutaneous coronary interventional (PCI) patients using a cardiac interventional x-ray system with state-of-the-art image enhancement and x-ray optimization, compared to the current generation x-ray system, and to determine the corresponding impact on clinical image quality. Patient procedure dose area product (DAP) and fluoroscopy duration of 131 PCI patient cases from each x-ray system were compared using a Wilcoxon test on median values. Significant reductions in patient dose ([Formula: see text]) were found for the new system with no significant change in fluoroscopy duration ([Formula: see text]); procedure DAP reduced by 64%, fluoroscopy DAP by 51%, and "cine" acquisition DAP by 76%. The image quality of 15 patient angiograms from each x-ray system (30 total) was scored by 75 clinical professionals on a continuous scale for the ability to determine the presence and severity of stenotic lesions; image quality scores were analyzed using a two-sample [Formula: see text]-test. Image quality was reduced by 9% ([Formula: see text]) for the new x-ray system. This demonstrates a substantial reduction in patient dose, from acquisition more than fluoroscopy imaging, with slightly reduced image quality, for the new x-ray system compared to the current generation system.
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Affiliation(s)
| | - Claire Keeble
- University of Leeds, Division of Epidemiology and Biostatistics, Leeds, United Kingdom
| | - Daniel Egleston
- University of Leeds, Division of Biomedical Imaging, Leeds, United Kingdom
| | - Josephine Bexon
- University of Leeds, Division of Biomedical Imaging, Leeds, United Kingdom
| | | | - Andrew G. Davies
- University of Leeds, Division of Biomedical Imaging, Leeds, United Kingdom
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Adkins AE, Hack LM, Bigdeli TB, Williamson VS, McMichael GO, Mamdani M, Edwards AC, Aliev F, Chan RF, Bhandari P, Raabe RC, Alaimo JT, Blackwell GG, Moscati A, Poland RS, Rood B, Patterson DG, Walsh D, Whitfield JB, Zhu G, Montgomery GW, Henders AK, Martin NG, Heath AC, Madden PAF, Frank J, Ridinger M, Wodarz N, Soyka M, Zill P, Ising M, Nöthen MM, Kiefer F, Rietschel M, Gelernter J, Sherva R, Koesterer R, Almasy L, Zhao H, Kranzler HR, Farrer LA, Maher BS, Prescott CA, Dick DM, Bacanu SA, Mathies LD, Davies AG, Vladimirov VI, Grotewiel M, Bowers MS, Bettinger JC, Webb BT, Miles MF, Kendler KS, Riley BP. Genomewide Association Study of Alcohol Dependence Identifies Risk Loci Altering Ethanol-Response Behaviors in Model Organisms. Alcohol Clin Exp Res 2017; 41:911-928. [PMID: 28226201 DOI: 10.1111/acer.13362] [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] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2016] [Accepted: 02/16/2017] [Indexed: 01/23/2023]
Abstract
BACKGROUND Alcohol dependence (AD) shows evidence for genetic liability, but genes influencing risk remain largely unidentified. METHODS We conducted a genomewide association study in 706 related AD cases and 1,748 unscreened population controls from Ireland. We sought replication in 15,496 samples of European descent. We used model organisms (MOs) to assess the role of orthologous genes in ethanol (EtOH)-response behaviors. We tested 1 primate-specific gene for expression differences in case/control postmortem brain tissue. RESULTS We detected significant association in COL6A3 and suggestive association in 2 previously implicated loci, KLF12 and RYR3. None of these signals are significant in replication. A suggestive signal in the long noncoding RNA LOC339975 is significant in case:control meta-analysis, but not in a population sample. Knockdown of a COL6A3 ortholog in Caenorhabditis elegans reduced EtOH sensitivity. Col6a3 expression correlated with handling-induced convulsions in mice. Loss of function of the KLF12 ortholog in C. elegans impaired development of acute functional tolerance (AFT). Klf12 expression correlated with locomotor activation following EtOH injection in mice. Loss of function of the RYR3 ortholog reduced EtOH sensitivity in C. elegans and rapid tolerance in Drosophila. The ryanodine receptor antagonist dantrolene reduced motivation to self-administer EtOH in rats. Expression of LOC339975 does not differ between cases and controls but is reduced in carriers of the associated rs11726136 allele in nucleus accumbens (NAc). CONCLUSIONS We detect association between AD and COL6A3, KLF12, RYR3, and LOC339975. Despite nonreplication of COL6A3, KLF12, and RYR3 signals, orthologs of these genes influence behavioral response to EtOH in MOs, suggesting potential involvement in human EtOH response and AD liability. The associated LOC339975 allele may influence gene expression in human NAc. Although the functions of long noncoding RNAs are poorly understood, there is mounting evidence implicating these genes in multiple brain functions and disorders.
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Affiliation(s)
- Amy E Adkins
- Virginia Commonwealth University Alcohol Research Center, Virginia Commonwealth University, Richmond, Virginia.,Department of Psychiatry, Virginia Commonwealth University, Richmond, Virginia
| | - Laura M Hack
- Virginia Commonwealth University Alcohol Research Center, Virginia Commonwealth University, Richmond, Virginia.,Department of Psychiatry, Virginia Commonwealth University, Richmond, Virginia
| | - Tim B Bigdeli
- Department of Psychiatry, Virginia Commonwealth University, Richmond, Virginia
| | - Vernell S Williamson
- Virginia Commonwealth University Alcohol Research Center, Virginia Commonwealth University, Richmond, Virginia.,Department of Psychiatry, Virginia Commonwealth University, Richmond, Virginia
| | - G Omari McMichael
- Virginia Commonwealth University Alcohol Research Center, Virginia Commonwealth University, Richmond, Virginia.,Department of Psychiatry, Virginia Commonwealth University, Richmond, Virginia
| | - Mohammed Mamdani
- Virginia Commonwealth University Alcohol Research Center, Virginia Commonwealth University, Richmond, Virginia.,Department of Psychiatry, Virginia Commonwealth University, Richmond, Virginia
| | - Alexis C Edwards
- Virginia Commonwealth University Alcohol Research Center, Virginia Commonwealth University, Richmond, Virginia.,Department of Psychiatry, Virginia Commonwealth University, Richmond, Virginia
| | - Fazil Aliev
- Virginia Commonwealth University Alcohol Research Center, Virginia Commonwealth University, Richmond, Virginia.,Department of Psychiatry, Virginia Commonwealth University, Richmond, Virginia
| | - Robin F Chan
- Virginia Commonwealth University Alcohol Research Center, Virginia Commonwealth University, Richmond, Virginia.,Department of Human & Molecular Genetics, Virginia Commonwealth University, Richmond, Virginia
| | - Poonam Bhandari
- Department of Human & Molecular Genetics, Virginia Commonwealth University, Richmond, Virginia
| | - Richard C Raabe
- Department of Pharmacology & Toxicology, Virginia Commonwealth University, Richmond, Virginia
| | - Joseph T Alaimo
- Department of Pharmacology & Toxicology, Virginia Commonwealth University, Richmond, Virginia
| | - GinaMari G Blackwell
- Department of Pharmacology & Toxicology, Virginia Commonwealth University, Richmond, Virginia
| | - Arden Moscati
- Virginia Commonwealth University Alcohol Research Center, Virginia Commonwealth University, Richmond, Virginia.,Department of Psychiatry, Virginia Commonwealth University, Richmond, Virginia
| | - Ryan S Poland
- Department of Psychiatry, Virginia Commonwealth University, Richmond, Virginia
| | - Benjamin Rood
- Department of Psychiatry, Virginia Commonwealth University, Richmond, Virginia
| | | | | | | | - John B Whitfield
- Genetic Epidemiology, QIMR Berghofer Medical Research Institute, Royal Brisbane and Women's Hospital, Brisbane, Qld, Australia
| | - Gu Zhu
- Genetic Epidemiology, QIMR Berghofer Medical Research Institute, Royal Brisbane and Women's Hospital, Brisbane, Qld, Australia
| | - Grant W Montgomery
- Genetic Epidemiology, QIMR Berghofer Medical Research Institute, Royal Brisbane and Women's Hospital, Brisbane, Qld, Australia
| | - Anjali K Henders
- Genetic Epidemiology, QIMR Berghofer Medical Research Institute, Royal Brisbane and Women's Hospital, Brisbane, Qld, Australia
| | - Nicholas G Martin
- Genetic Epidemiology, QIMR Berghofer Medical Research Institute, Royal Brisbane and Women's Hospital, Brisbane, Qld, Australia
| | - Andrew C Heath
- Department of Psychiatry, Washington University School of Medicine, St. Louis, Missouri
| | - Pamela A F Madden
- Department of Psychiatry, Washington University School of Medicine, St. Louis, Missouri
| | - Josef Frank
- Department of Genetic Epidemiology in Psychiatry, Central Institute of Mental Health, Medical Faculty Mannheim/Heidelberg University, Mannheim, Germany
| | - Monika Ridinger
- Department of Psychiatry, University Hospital Regensburg, University of Regensburg, Regensburg, Germany
| | - Norbert Wodarz
- Department of Psychiatry, University Hospital Regensburg, University of Regensburg, Regensburg, Germany
| | - Michael Soyka
- Privatklinik Meiringen, Meiringen, Switzerland.,Department of Psychiatry and Psychotherapy, University of Munich, Munich, Germany
| | - Peter Zill
- Department of Psychiatry and Psychotherapy, University of Munich, Munich, Germany
| | - Marcus Ising
- Department of Molecular Psychology, Max-Planck-Institute of Psychiatry, Munich, Germany
| | - Markus M Nöthen
- Department of Genomics, Life & Brain Center, University of Bonn, Bonn, Germany.,Institute of Human Genetics, University of Bonn, Bonn, Germany.,German Center for Neurodegenerative Diseases (DZNE), University of Bonn, Bonn, Germany
| | - Falk Kiefer
- Department of Addictive Behavior and Addiction Medicine, Central Institute of Mental Health, Medical Faculty Mannheim/Heidelberg University, Mannheim, Germany
| | - Marcella Rietschel
- Department of Genetic Epidemiology in Psychiatry, Central Institute of Mental Health, Medical Faculty Mannheim/Heidelberg University, Mannheim, Germany
| | | | - Joel Gelernter
- Department of Psychiatry, Yale University School of Medicine, New Haven, Connecticut.,Department of Neurobiology, Yale University School of Medicine, New Haven, Connecticut.,Department of Genetics, Yale University School of Medicine, New Haven, Connecticut.,Department of Psychiatry, VA CT Healthcare Center, West Haven, Connecticut
| | - Richard Sherva
- Department of Medicine (Biomedical Genetics), Boston University School of Medicine, Boston, Massachusetts
| | - Ryan Koesterer
- Department of Medicine (Biomedical Genetics), Boston University School of Medicine, Boston, Massachusetts
| | - Laura Almasy
- Department of Genetics, Texas Biomedical Research Institute, San Antonio, Texas
| | - Hongyu Zhao
- Department of Genetics, Yale University School of Medicine, New Haven, Connecticut.,Department of Biostatistics, Yale University School of Medicine, New Haven, Connecticut
| | - Henry R Kranzler
- Department of Psychiatry, Treatment Research Center, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania.,Philadelphia VA Medical Center, VISN 4 MIRECC, Philadelphia, Pennsylvania
| | - Lindsay A Farrer
- Department of Psychiatry, VA CT Healthcare Center, West Haven, Connecticut.,Department of Medicine (Biomedical Genetics), Boston University School of Medicine, Boston, Massachusetts.,Department of Neurology, Boston University School of Medicine, Boston, Massachusetts.,Department of Ophthalmology, Boston University School of Medicine, Boston, Massachusetts.,Department of Epidemiology, Boston University School of Public Health, Boston, Massachusetts.,Department of Biostatistics, Boston University School of Public Health, Boston, Massachusetts
| | - Brion S Maher
- Department of Mental Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
| | - Carol A Prescott
- Department of Psychology, University of Southern California, Los Angeles, California
| | - Danielle M Dick
- Virginia Commonwealth University Alcohol Research Center, Virginia Commonwealth University, Richmond, Virginia.,Department of Psychiatry, Virginia Commonwealth University, Richmond, Virginia.,Department of Human & Molecular Genetics, Virginia Commonwealth University, Richmond, Virginia
| | - Silviu A Bacanu
- Virginia Commonwealth University Alcohol Research Center, Virginia Commonwealth University, Richmond, Virginia.,Department of Psychiatry, Virginia Commonwealth University, Richmond, Virginia
| | - Laura D Mathies
- Department of Pharmacology & Toxicology, Virginia Commonwealth University, Richmond, Virginia
| | - Andrew G Davies
- Virginia Commonwealth University Alcohol Research Center, Virginia Commonwealth University, Richmond, Virginia.,Department of Pharmacology & Toxicology, Virginia Commonwealth University, Richmond, Virginia
| | - Vladimir I Vladimirov
- Virginia Commonwealth University Alcohol Research Center, Virginia Commonwealth University, Richmond, Virginia.,Department of Psychiatry, Virginia Commonwealth University, Richmond, Virginia.,Lieber Institute for Brain Development, Johns Hopkins University, Baltimore, Maryland.,Center for Biomarker Research and Personalized Medicine, School of Pharmacy, Virginia Commonwealth University, Richmond, Virginia
| | - Mike Grotewiel
- Virginia Commonwealth University Alcohol Research Center, Virginia Commonwealth University, Richmond, Virginia.,Department of Human & Molecular Genetics, Virginia Commonwealth University, Richmond, Virginia
| | - M Scott Bowers
- Virginia Commonwealth University Alcohol Research Center, Virginia Commonwealth University, Richmond, Virginia.,Department of Psychiatry, Virginia Commonwealth University, Richmond, Virginia.,Department of Pharmacology & Toxicology, Virginia Commonwealth University, Richmond, Virginia
| | - Jill C Bettinger
- Virginia Commonwealth University Alcohol Research Center, Virginia Commonwealth University, Richmond, Virginia.,Department of Pharmacology & Toxicology, Virginia Commonwealth University, Richmond, Virginia
| | - Bradley T Webb
- Virginia Commonwealth University Alcohol Research Center, Virginia Commonwealth University, Richmond, Virginia.,Department of Psychiatry, Virginia Commonwealth University, Richmond, Virginia
| | - Michael F Miles
- Virginia Commonwealth University Alcohol Research Center, Virginia Commonwealth University, Richmond, Virginia.,Department of Human & Molecular Genetics, Virginia Commonwealth University, Richmond, Virginia.,Department of Pharmacology & Toxicology, Virginia Commonwealth University, Richmond, Virginia
| | - Kenneth S Kendler
- Virginia Commonwealth University Alcohol Research Center, Virginia Commonwealth University, Richmond, Virginia.,Department of Psychiatry, Virginia Commonwealth University, Richmond, Virginia.,Department of Human & Molecular Genetics, Virginia Commonwealth University, Richmond, Virginia
| | - Brien P Riley
- Virginia Commonwealth University Alcohol Research Center, Virginia Commonwealth University, Richmond, Virginia.,Department of Psychiatry, Virginia Commonwealth University, Richmond, Virginia.,Department of Human & Molecular Genetics, Virginia Commonwealth University, Richmond, Virginia
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Joshi A, Gislason-Lee AJ, Keeble C, Sivananthan UM, Davies AG. Can image enhancement allow radiation dose to be reduced whilst maintaining the perceived diagnostic image quality required for coronary angiography? Br J Radiol 2017; 90:20160660. [PMID: 28124572 DOI: 10.1259/bjr.20160660] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
OBJECTIVE The aim of this research was to quantify the reduction in radiation dose facilitated by image processing alone for percutaneous coronary intervention (PCI) patient angiograms, without reducing the perceived image quality required to confidently make a diagnosis. METHODS Incremental amounts of image noise were added to five PCI angiograms, simulating the angiogram as having been acquired at corresponding lower dose levels (10-89% dose reduction). 16 observers with relevant experience scored the image quality of these angiograms in 3 states-with no image processing and with 2 different modern image processing algorithms applied. These algorithms are used on state-of-the-art and previous generation cardiac interventional X-ray systems. Ordinal regression allowing for random effects and the delta method were used to quantify the dose reduction possible by the processing algorithms, for equivalent image quality scores. RESULTS Observers rated the quality of the images processed with the state-of-the-art and previous generation image processing with a 24.9% and 15.6% dose reduction, respectively, as equivalent in quality to the unenhanced images. The dose reduction facilitated by the state-of-the-art image processing relative to previous generation processing was 10.3%. CONCLUSION Results demonstrate that statistically significant dose reduction can be facilitated with no loss in perceived image quality using modern image enhancement; the most recent processing algorithm was more effective in preserving image quality at lower doses. Advances in knowledge: Image enhancement was shown to maintain perceived image quality in coronary angiography at a reduced level of radiation dose using computer software to produce synthetic images from real angiograms simulating a reduction in dose.
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Affiliation(s)
- Anuja Joshi
- 1 Division of Biomedical Imaging, University of Leeds, Leeds, UK
| | | | - Claire Keeble
- 1 Division of Biomedical Imaging, University of Leeds, Leeds, UK.,2 Division of Epidemiology and Biostatistics, University of Leeds, Leeds, UK
| | | | - Andrew G Davies
- 1 Division of Biomedical Imaging, University of Leeds, Leeds, UK
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Kengyelics SM, Gislason-Lee AJ, Keeble C, Magee DR, Davies AG. Noise estimation in cardiac x-ray imaging: a machine vision approach. Biomed Phys Eng Express 2016. [DOI: 10.1088/2057-1976/2/6/065014] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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28
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Han YJ, Li LH, Grier A, Chen L, Valavanis A, Zhu J, Freeman JR, Isac N, Colombelli R, Dean P, Davies AG, Linfield EH. Extraction-controlled terahertz frequency quantum cascade lasers with a diagonal LO-phonon extraction and injection stage. Opt Express 2016; 24:28583-28593. [PMID: 27958502 DOI: 10.1364/oe.24.028583] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
We report an extraction-controlled terahertz (THz)-frequency quantum cascade laser design in which a diagonal LO-phonon scattering process is used to achieve efficient current injection into the upper laser level of each period and simultaneously extract electrons from the adjacent period. The effects of the diagonality of the radiative transition are investigated, and a design with a scaled oscillator strength of 0.45 is shown experimentally to provide the highest temperature performance. A 3.3 THz device processed into a double-metal waveguide configuration operated up to 123 K in pulsed mode, with a threshold current density of 1.3 kA/cm2 at 10 K. The QCL structures are modeled using an extended density matrix approach, and the large threshold current is attributed to parasitic current paths associated with the upper laser levels. The simplicity of this design makes it an ideal platform to investigate the scattering injection process.
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Gislason-Lee AJ, Keeble C, Malkin CJ, Egleston D, Bexon J, Kengyelics SM, Blackman D, Davies AG. Impact of latest generation cardiac interventional X-ray equipment on patient image quality and radiation dose for trans-catheter aortic valve implantations. Br J Radiol 2016; 89:20160269. [PMID: 27610932 PMCID: PMC5124836 DOI: 10.1259/bjr.20160269] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2016] [Revised: 08/31/2016] [Accepted: 09/08/2016] [Indexed: 01/13/2023] Open
Abstract
OBJECTIVES This study aimed to determine the impact on radiation dose and image quality of a new cardiac interventional X-ray system for trans-catheter aortic valve implantation (TAVI) patients compared to the previously-used cardiac X-ray system. METHODS Patient dose and image data were retrospectively collected from a Philips AlluraClarity (new) and Siemens Axion Artis (reference) X-ray system. Patient dose area product (DAP) and fluoroscopy duration of 41 patient cases from each X-ray system were compared using a Wilcoxon test. Ten patient aortograms from each X-ray system were scored by 32 observers on a continuous scale to assess the clinical image quality at the given phase of the TAVI procedure. Scores were dichotomised by acceptability and analysed using a Chi-squared test. RESULTS Significant reductions in patient dose (p << 0.001) were found for the new system with no significant change in fluoroscopy duration (p = 0.052); procedure DAP reduced by 55%, fluoroscopy DAP by 48% and "cine" acquisition DAP by 61%. There was no significant difference between image quality scores of the two X-ray systems (p = 0.06). CONCLUSIONS The new cardiac X-ray system demonstrated a very significant reduction in patient dose with no loss of clinical image quality. Advances in Knowledge: The huge growth of TAVI may impact on the radiation exposure of cardiac patients and particularly on operators including anaesthetists; cumulative exposure of interventional cardiologists performing high volume TAVI over 30-40 years may be harmful. The Phillips Clarity upgrade including improved image enhancement and optimised X-ray settings significantly reduced radiation without reducing clinically acceptable image quality.
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Affiliation(s)
| | - Claire Keeble
- Division of Epidemiology and Biostatistics, University of Leeds, Leeds, UK
| | | | - Daniel Egleston
- Division of Biomedical Imaging, University of Leeds, Leeds, UK
| | - Josephine Bexon
- Division of Biomedical Imaging, University of Leeds, Leeds, UK
| | | | - Daniel Blackman
- Department of Cardiology, Leeds General Infirmary, Leeds, UK
| | - Andrew G Davies
- Division of Biomedical Imaging, University of Leeds, Leeds, UK
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Abstract
We present a method for the specific, spatially targeted attachment of DNA molecules to lithographically patterned gold surfaces-demonstrated by bridging DNA strands across nanogap electrode structures. An alkanethiol self-assembled monolayer was employed as a molecular resist, which could be selectively removed via electrochemical desorption, allowing the binding of thiolated DNA anchoring oligonucleotides to each electrode. After introducing a bridging DNA molecule with single-stranded ends complementary to the electrode-tethered anchoring oligonucleotides, the positioning of the DNA molecule across the electrode gap, driven by self-assembly, occurred autonomously. This demonstrates control of molecule positioning with resolution limited only by the underlying patterned structure, does not require any alignment, is carried out entirely under biologically compatible conditions, and is scalable.
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Affiliation(s)
- M Szymonik
- School of Electronic and Electrical Engineering, University of Leeds, Leeds LS2 9JT, UK
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32
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Keeble C, Baxter PD, Gislason-Lee AJ, Treadgold LA, Davies AG. Methods for the analysis of ordinal response data in medical image quality assessment. Br J Radiol 2016; 89:20160094. [PMID: 26975497 PMCID: PMC5257322 DOI: 10.1259/bjr.20160094] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [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: 01/26/2016] [Revised: 03/02/2016] [Accepted: 03/10/2016] [Indexed: 01/10/2023] Open
Abstract
The assessment of image quality in medical imaging often requires observers to rate images for some metric or detectability task. These subjective results are used in optimization, radiation dose reduction or system comparison studies and may be compared to objective measures from a computer vision algorithm performing the same task. One popular scoring approach is to use a Likert scale, then assign consecutive numbers to the categories. The mean of these response values is then taken and used for comparison with the objective or second subjective response. Agreement is often assessed using correlation coefficients. We highlight a number of weaknesses in this common approach, including inappropriate analyses of ordinal data and the inability to properly account for correlations caused by repeated images or observers. We suggest alternative data collection and analysis techniques such as amendments to the scale and multilevel proportional odds models. We detail the suitability of each approach depending upon the data structure and demonstrate each method using a medical imaging example. Whilst others have raised some of these issues, we evaluated the entire study from data collection to analysis, suggested sources for software and further reading, and provided a checklist plus flowchart for use with any ordinal data. We hope that raised awareness of the limitations of the current approaches will encourage greater method consideration and the utilization of a more appropriate analysis. More accurate comparisons between measures in medical imaging will lead to a more robust contribution to the imaging literature and ultimately improved patient care.
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Affiliation(s)
- Claire Keeble
- Division of Epidemiology and Biostatistics, University of Leeds, Leeds, UK
- Division of Biomedical Imaging, University of Leeds, Leeds, UK
| | - Paul D Baxter
- Division of Epidemiology and Biostatistics, University of Leeds, Leeds, UK
| | | | | | - Andrew G Davies
- Division of Biomedical Imaging, University of Leeds, Leeds, UK
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Baillergeau M, Maussang K, Nirrengarten T, Palomo J, Li LH, Linfield EH, Davies AG, Dhillon S, Tignon J, Mangeney J. Diffraction-limited ultrabroadband terahertz spectroscopy. Sci Rep 2016; 6:24811. [PMID: 27142959 PMCID: PMC4855139 DOI: 10.1038/srep24811] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2016] [Accepted: 04/05/2016] [Indexed: 11/09/2022] Open
Abstract
Diffraction is the ultimate limit at which details of objects can be resolved in conventional optical spectroscopy and imaging systems. In the THz spectral range, spectroscopy systems increasingly rely on ultra-broadband radiation (extending over more 5 octaves) making a great challenge to reach resolution limited by diffraction. Here, we propose an original easy-to-implement wavefront manipulation concept to achieve ultrabroadband THz spectroscopy system with diffraction-limited resolution. Applying this concept to a large-area photoconductive emitter, we demonstrate diffraction-limited ultra-broadband spectroscopy system up to 14.5 THz with a dynamic range of 10(3). The strong focusing of ultrabroadband THz radiation provided by our approach is essential for investigating single micrometer-scale objects such as graphene flakes or living cells, and besides for achieving intense ultra-broadband THz electric fields.
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Affiliation(s)
- M Baillergeau
- Laboratoire Pierre Aigrain, Ecole Normale Supérieure, CNRS (UMR 8551), Université P. et M. Curie, Université D. Diderot, 75231 Paris Cedex 05, France
| | - K Maussang
- Laboratoire Pierre Aigrain, Ecole Normale Supérieure, CNRS (UMR 8551), Université P. et M. Curie, Université D. Diderot, 75231 Paris Cedex 05, France
| | - T Nirrengarten
- Laboratoire Pierre Aigrain, Ecole Normale Supérieure, CNRS (UMR 8551), Université P. et M. Curie, Université D. Diderot, 75231 Paris Cedex 05, France
| | - J Palomo
- Laboratoire Pierre Aigrain, Ecole Normale Supérieure, CNRS (UMR 8551), Université P. et M. Curie, Université D. Diderot, 75231 Paris Cedex 05, France
| | - L H Li
- School of Electronic and Electrical Engineering, University of Leeds, Woodhouse Lane, Leeds LS29JT, UK
| | - E H Linfield
- School of Electronic and Electrical Engineering, University of Leeds, Woodhouse Lane, Leeds LS29JT, UK
| | - A G Davies
- School of Electronic and Electrical Engineering, University of Leeds, Woodhouse Lane, Leeds LS29JT, UK
| | - S Dhillon
- Laboratoire Pierre Aigrain, Ecole Normale Supérieure, CNRS (UMR 8551), Université P. et M. Curie, Université D. Diderot, 75231 Paris Cedex 05, France
| | - J Tignon
- Laboratoire Pierre Aigrain, Ecole Normale Supérieure, CNRS (UMR 8551), Université P. et M. Curie, Université D. Diderot, 75231 Paris Cedex 05, France
| | - J Mangeney
- Laboratoire Pierre Aigrain, Ecole Normale Supérieure, CNRS (UMR 8551), Université P. et M. Curie, Université D. Diderot, 75231 Paris Cedex 05, France
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Sharma R, Deacon SE, Nowak D, George SE, Szymonik MP, Tang AAS, Tomlinson DC, Davies AG, McPherson MJ, Wälti C. Label-free electrochemical impedance biosensor to detect human interleukin-8 in serum with sub-pg/ml sensitivity. Biosens Bioelectron 2016; 80:607-613. [PMID: 26897263 PMCID: PMC4785862 DOI: 10.1016/j.bios.2016.02.028] [Citation(s) in RCA: 79] [Impact Index Per Article: 9.9] [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: 11/15/2015] [Revised: 02/08/2016] [Accepted: 02/10/2016] [Indexed: 01/01/2023]
Abstract
Biosensors with high sensitivity and short time-to-result that are capable of detecting biomarkers in body fluids such as serum are an important prerequisite for early diagnostics in modern healthcare provision. Here, we report the development of an electrochemical impedance-based sensor for the detection in serum of human interleukin-8 (IL-8), a pro-angiogenic chemokine implicated in a wide range of inflammatory diseases. The sensor employs a small and robust synthetic non-antibody capture protein based on a cystatin scaffold that displays high affinity for human IL-8 with a KD of 35±10 nM and excellent ligand specificity. The change in the phase of the electrochemical impedance from the serum baseline, ∆θ(ƒ), measured at 0.1 Hz, was used as the measure for quantifying IL-8 concentration in the fluid. Optimal sensor signal was observed after 15 min incubation, and the sensor exhibited a linear response versus logarithm of IL-8 concentration from 900 fg/ml to 900 ng/ml. A detection limit of around 90 fg/ml, which is significantly lower than the basal clinical levels of 5–10 pg/ml, was observed. Our results are significant for the development of point-of-care and early diagnostics where high sensitivity and short time-to-results are essential. A label-free electrochemical impedance-based sensor for the detection of human interleukin-8 (IL-8) in full serum was developed. Detection limit of 90 fg/ml and time-to-result of 15 min was found. A large dynamic range of the sensor was observed, with sensor response linear vs logarithm of IL-8 concentration from 900 fg/ml to 900 ng/ml. The sensor employs a small and robust synthetic non-antibody capture protein, with high stability and excellent ligand specificity. Findings are particularly relevant for the development of point-of-care and early diagnosis sensors where high sensitivity and short time-to-results are essential.
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Affiliation(s)
- R Sharma
- School of Electronic and Electrical Engineering, University of Leeds, Woodhouse Lane, Leeds LS2 9JT, UK
| | - S E Deacon
- School of Molecular and Cellular Biology, University of Leeds, Woodhouse Lane, Leeds LS2 9JT, UK
| | - D Nowak
- School of Electronic and Electrical Engineering, University of Leeds, Woodhouse Lane, Leeds LS2 9JT, UK
| | - S E George
- School of Molecular and Cellular Biology, University of Leeds, Woodhouse Lane, Leeds LS2 9JT, UK
| | - M P Szymonik
- School of Electronic and Electrical Engineering, University of Leeds, Woodhouse Lane, Leeds LS2 9JT, UK
| | - A A S Tang
- School of Molecular and Cellular Biology, University of Leeds, Woodhouse Lane, Leeds LS2 9JT, UK; BioScreening Technology Group, Astbury Building, University of Leeds, Leeds LS2 9JT, UK
| | - D C Tomlinson
- School of Molecular and Cellular Biology, University of Leeds, Woodhouse Lane, Leeds LS2 9JT, UK; BioScreening Technology Group, Astbury Building, University of Leeds, Leeds LS2 9JT, UK
| | - A G Davies
- School of Electronic and Electrical Engineering, University of Leeds, Woodhouse Lane, Leeds LS2 9JT, UK
| | - M J McPherson
- School of Molecular and Cellular Biology, University of Leeds, Woodhouse Lane, Leeds LS2 9JT, UK; BioScreening Technology Group, Astbury Building, University of Leeds, Leeds LS2 9JT, UK.
| | - C Wälti
- School of Electronic and Electrical Engineering, University of Leeds, Woodhouse Lane, Leeds LS2 9JT, UK.
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Wang F, Kundu I, Chen L, Li L, Linfield EH, Davies AG, Moumdji S, Colombelli R, Mangeney J, Tignon J, Dhillon SS. Engineered far-fields of metal-metal terahertz quantum cascade lasers with integrated planar horn structures. Opt Express 2016; 24:2174-2182. [PMID: 26906793 DOI: 10.1364/oe.24.002174] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
The far-field emission profile of terahertz quantum cascade lasers (QCLs) in metal-metal waveguides is controlled in directionality and form through planar horn-type shape structures, whilst conserving a broad spectral response. The structures produce a gradual change in the high modal confinement of the waveguides and permit an improved far-field emission profile and resulting in a four-fold increase in the emitted output power. The two-dimensional far-field patterns are measured at 77 K and are agreement in with 3D modal simulations. The influence of parasitic high-order transverse modes is shown to be controlled by engineering the horn structure (ridge and horn widths), allowing only the fundamental mode to be coupled out.
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Clarke A, Flowers MJ, Davies AG, Fernandes J, Jones S. Morbidity associated with anterior iliac crest bone graft harvesting in children undergoing orthopaedic surgery: a prospective review. J Child Orthop 2015; 9:411-6. [PMID: 26438166 PMCID: PMC4619364 DOI: 10.1007/s11832-015-0698-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/17/2015] [Accepted: 09/19/2015] [Indexed: 02/03/2023] Open
Abstract
PURPOSE Autologous iliac crest bone grafting is an integral part of many orthopaedic surgical procedures. Several studies have documented morbidity and prolonged pain following iliac crest bone graft harvesting in adults; however, in children there is a paucity of information. The purpose of the present study was to quantify the degree of pain and morbidity associated with anterior iliac crest graft harvesting in children undergoing non-spinal orthopaedic surgery. METHODS Patients were prospectively enrolled prior to orthopaedic surgery. A patient self-reported visual analogue score was used to record pain at specified time points following surgery. In addition, the patients were reviewed at 2 and 6 weeks, 3 months and 1 year after surgery to record any complications. RESULTS Data was collected on 33 patients (34 graft sites). Only one patient (2.94 %) had a complication, namely an injury to the lateral femoral cutaneous nerve. This resolved 3 months after surgery. 89 % of patients had no pain at the iliac crest graft harvest site 3 months after surgery. The three patients who had pain at 3 months had visual analogue scores of 1.0, 1.1 and 1.3, respectively. CONCLUSION This series reveals a very low complication rate and minimal iliac crest graft harvest site pain in children undergoing non-spinal orthopaedic surgery. In addition, the pain experienced is short-lived.
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Affiliation(s)
- A Clarke
- Department of Orthopaedics, Sheffield Children's Hospital, Sheffield, UK
| | - M J Flowers
- Department of Orthopaedics, Sheffield Children's Hospital, Sheffield, UK
| | - A G Davies
- Department of Orthopaedics, Sheffield Children's Hospital, Sheffield, UK
| | - J Fernandes
- Department of Orthopaedics, Sheffield Children's Hospital, Sheffield, UK
| | - S Jones
- Department of Orthopaedics, Al Ahli Hospital, Doha, Qatar.
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Gislason-Lee AJ, Tunstall CM, Kengyelics SK, Cowen AR, Davies AG. Technical Note: Impact on detective quantum efficiency of edge angle determination method by International Electrotechnical Commission methodology for cardiac x-ray image detectors. Med Phys 2015; 42:4423-7. [PMID: 26233172 DOI: 10.1118/1.4923178] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
PURPOSE Cardiac x-ray detectors are used to acquire moving images in real-time for angiography and interventional procedures. Detective quantum efficiency (DQE) is not generally measured on these dynamic detectors; the required "for processing" image data and control of x-ray settings have not been accessible. By 2016, USA hospital physicists will have the ability to measure DQE and will likely utilize the International Electrotechnical Commission (IEC) standard for measuring DQE of dynamic x-ray imaging devices. The current IEC standard requires an image of a tilted tungsten edge test object to obtain modulation transfer function (MTF) for DQE calculation. It specifies the range of edge angles to use; however, it does not specify a preferred method to determine this angle for image analysis. The study aimed to answer the question "will my choice in method impact my results?" Four different established edge angle determination methods were compared to investigate the impact on DQE. METHODS Following the IEC standard, edge and flat field images were acquired on a cardiac flat-panel detector to calculate MTF and noise power spectrum, respectively, to determine DQE. Accuracy of the methods in determining the correct angle was ascertained using a simulated edge image with known angulations. Precision of the methods was ascertained using variability of MTF and DQE, calculated via bootstrapping. RESULTS Three methods provided near equal angles and the same MTF while the fourth, with an angular difference of 6%, had a MTF lower by 3% at 1.5 mm(-1) spatial frequency and 8% at 2.5 mm(-1); corresponding DQE differences were 6% at 1.5 mm(-1) and 17% at 2.5 mm(-1); differences were greater than standard deviations in the measurements. CONCLUSIONS DQE measurements may vary by a significant amount, depending on the method used to determine the edge angle when following the IEC standard methodology for a cardiac x-ray detector. The most accurate and precise methods are recommended for absolute assessments and reproducible measurements, respectively.
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Affiliation(s)
- Amber J Gislason-Lee
- LXi Research, Division of Biomedical Imaging, University of Leeds, Worsley Building, Clarendon Way, Leeds LS2 9JT, United Kingdom
| | - Clare M Tunstall
- LXi Research, Division of Biomedical Imaging, University of Leeds, Worsley Building, Clarendon Way, Leeds LS2 9JT, United Kingdom
| | - Stephen K Kengyelics
- LXi Research, Division of Biomedical Imaging, University of Leeds, Worsley Building, Clarendon Way, Leeds LS2 9JT, United Kingdom
| | - Arnold R Cowen
- LXi Research, Division of Biomedical Imaging, University of Leeds, Worsley Building, Clarendon Way, Leeds LS2 9JT, United Kingdom
| | - Andrew G Davies
- LXi Research, Division of Biomedical Imaging, University of Leeds, Worsley Building, Clarendon Way, Leeds LS2 9JT, United Kingdom
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Davies AG, Blackwell GG, Raabe RC, Bettinger JC. An Assay for Measuring the Effects of Ethanol on the Locomotion Speed of Caenorhabditis elegans. J Vis Exp 2015. [PMID: 25938273 DOI: 10.3791/52681] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
Alcohol use disorders are a significant public health concern, for which there are few effective treatment strategies. One difficulty that has delayed the development of more effective treatments is the relative lack of understanding of the molecular underpinnings of the effects of ethanol on behavior. The nematode, Caenorhabditis elegans (C. elegans), provides a useful model in which to generate and test hypotheses about the molecular effects of ethanol. Here, we describe an assay that has been developed and used to examine the roles of particular genes and environmental factors in behavioral responses to ethanol, in which locomotion is the behavioral output. Ethanol dose-dependently causes an acute depression of crawling on an agar surface. The effects are dynamic; animals exposed to a high concentration demonstrate an initial strong depression of crawling, referred to here as initial sensitivity, and then partially recover locomotion speed despite the continued presence of the drug. This ethanol-induced behavioral plasticity is referred to here as the development of acute functional tolerance. This assay has been used to demonstrate that these two phenotypes are distinct and genetically separable. The straightforward locomotion assay described here is suitable for examining the effects of both genetic and environmental manipulations on these acute behavioral responses to ethanol in C. elegans.
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Affiliation(s)
- Andrew G Davies
- Department of Pharmacology and Toxicology, Virginia Commonwealth University; VCU Alcohol Research Center, Virginia Commonwealth University
| | - GinaMari G Blackwell
- Department of Pharmacology and Toxicology, Virginia Commonwealth University; VCU Alcohol Research Center, Virginia Commonwealth University
| | - Richard C Raabe
- Department of Pharmacology and Toxicology, Virginia Commonwealth University
| | - Jill C Bettinger
- Department of Pharmacology and Toxicology, Virginia Commonwealth University; VCU Alcohol Research Center, Virginia Commonwealth University;
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Keeley J, Dean P, Valavanis A, Bertling K, Lim YL, Alhathlool R, Taimre T, Li LH, Indjin D, Rakić AD, Linfield EH, Davies AG. Three-dimensional terahertz imaging using swept-frequency feedback interferometry with a quantum cascade laser. Opt Lett 2015; 40:994-997. [PMID: 25768165 DOI: 10.1364/ol.40.000994] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
We demonstrate coherent three-dimensional terahertz imaging by frequency modulation of a quantum cascade laser in a compact and experimentally simple self-mixing scheme. Through this approach, we can realize significantly faster acquisition rates compared to previous schemes employing longitudinal mechanical scanning of a sample. We achieve a depth resolution of better than 0.1 μm with a power noise spectral density below -50 dB/Hz, for a sampling time of 10 ms/pixel.
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40
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Dean P, Keeley J, Valavanis A, Bertling K, Lim YL, Taimre T, Alhathlool R, Li LH, Indjin D, Rakić AD, Linfield EH, Davies AG. Active phase-nulling of the self-mixing phase in a terahertz frequency quantum cascade laser. Opt Lett 2015; 40:950-953. [PMID: 25768154 DOI: 10.1364/ol.40.000950] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
We demonstrate an active phase-nulling scheme for terahertz (THz) frequency quantum cascade lasers (QCLs) under optical feedback, by active electronic feedback control of the emission frequency. Using this scheme, the frequency tuning rate of a THz QCL is characterized, with significantly reduced experimental complexity compared to alternative approaches. Furthermore, we demonstrate real-time displacement sensing of targets, overcoming the resolution limits imposed by quantization in previously implemented fringe-counting methods. Our approach is readily applicable to high-frequency vibrometry and surface profiling of targets, as well as frequency-stabilization schemes for THz QCLs.
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Houver S, Cavalié P, St-Jean MR, Amanti MI, Sirtori C, Li LH, Davies AG, Linfield EH, Pereira TAS, Lebreton A, Tignon J, Dhillon SS. Optical sideband generation up to room temperature with mid-infrared quantum cascade lasers. Opt Express 2015; 23:4012-4020. [PMID: 25836440 DOI: 10.1364/oe.23.004012] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Mid-infrared (MIR) sideband generation on a near infrared (NIR) optical carrier is demonstrated within a quantum cascade laser (QCL). By employing an externally injected NIR beam, E(NIR), that is resonant with the interband transitions of the quantum wells in the QCL, the nonlinear susceptibility is enhanced, leading to both frequency mixing and sideband generation. A GaAs-based MIR QCL (E(QCL) = 135 meV) with an aluminum-reinforced waveguide was utilized to overlap the NIR and MIR modes with the optical nonlinearity of the active region. The resulting difference sideband (E(NIR) - E(QCL)) shows a resonant behavior as a function of NIR pump wavelength and a maximum second order nonlinear susceptibility, χ((2)), of ~1 nm/V was obtained. Further, the sideband intensity showed little dependence with the operating temperature of the QCL, allowing sideband generation to be realized at room temperature.
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Li LH, Zhu JX, Chen L, Davies AG, Linfield EH. The MBE growth and optimization of high performance terahertz frequency quantum cascade lasers. Opt Express 2015; 23:2720-2729. [PMID: 25836134 DOI: 10.1364/oe.23.002720] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The technique of molecular beam epitaxy has recently been used to demonstrate the growth of terahertz frequency GaAs/AlGaAs quantum cascade lasers (QCL) with Watt-level optical output powers. In this paper, we discuss the critical importance of achieving accurate layer thicknesses and alloy compositions during growth, and demonstrate that precise growth control as well as run-to-run growth reproducibility is possible. We also discuss the importance of minimizing background doping level in maximizing QCL performance. By selecting high-performance active region designs, and optimizing the injection doping level and device fabrication, we demonstrate total optical (two-facet) output powers as high as 1.56 W.
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Wolstenhulme S, Davies AG, Keeble C, Moore S, Evans JA. Agreement between objective and subjective assessment of image quality in ultrasound abdominal aortic aneurism screening. Br J Radiol 2014; 88:20140482. [PMID: 25494526 DOI: 10.1259/bjr.20140482] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
OBJECTIVE To investigate agreement between objective and subjective assessment of image quality of ultrasound scanners used for abdominal aortic aneurysm (AAA) screening. METHODS Nine ultrasound scanners were used to acquire longitudinal and transverse images of the abdominal aorta. 100 images were acquired per scanner from which 5 longitudinal and 5 transverse images were randomly selected. 33 practitioners scored 90 images blinded to the scanner type and subject characteristics and were required to state whether or not the images were of adequate diagnostic quality. Odds ratios were used to rank the subjective image quality of the scanners. For objective testing, three standard test objects were used to assess penetration and resolution and used to rank the scanners. RESULTS The subjective diagnostic image quality was ten times greater for the highest ranked scanner than for the lowest ranked scanner. It was greater at depths of <5.0 cm (odds ratio, 6.69; 95% confidence interval, 3.56, 12.57) than at depths of 15.1-20.0 cm. There was a larger range of odds ratios for transverse images than for longitudinal images. No relationship was seen between subjective scanner rankings and test object scores. CONCLUSION Large variation was seen in the image quality when evaluated both subjectively and objectively. OBJECTIVE scores did not predict subjective scanner rankings. Further work is needed to investigate the utility of both subjective and objective image quality measurements. ADVANCES IN KNOWLEDGE Ratings of clinical image quality and image quality measured using test objects did not agree, even in the limited scenario of AAA screening.
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Davies AG, Gislason-Lee AJ, Cowen AR, Kengyelics SM, Lupton M, Moore J, Sivananthan M. Does the use of additional X-ray beam filtration during cine acquisition reduce clinical image quality and effective dose in cardiac interventional imaging? Radiat Prot Dosimetry 2014; 162:597-604. [PMID: 24563525 DOI: 10.1093/rpd/ncu020] [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] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
The impact of spectral filtration in digital ('cine') acquisition was investigated using a flat panel cardiac interventional X-ray imaging system. A 0.1-mm copper (Cu) and 1.0-mm aluminium (Al) filter added to the standard acquisition mode created the filtered mode for comparison. Image sequences of 35 patients were acquired, a double-blind subjective image quality assessment was completed and dose-area product (DAP) rates were calculated. Entrance surface dose (ESD) and effective dose (E) rates were determined for 20- and 30-cm phantoms. Phantom ESD fell by 28 and 41 % and E by 1 and 0.7 %, for the 20- and 30-cm phantoms, respectively, when using the filtration. Patient DAP rates fell by 43 % with no statistically significant difference in clinical image quality. Adding 0.1-mm Cu and 1.0-mm Al filtration in acquisition substantially reduces patient ESD and DAP, with no significant change in E or clinical image quality.
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Affiliation(s)
- Andrew G Davies
- Division of Medical Physics, University of Leeds, Room 8.001 Worsley Building, Clarendon Way, Leeds LS2 9JT, UK
| | - Amber J Gislason-Lee
- Division of Medical Physics, University of Leeds, Room 8.001 Worsley Building, Clarendon Way, Leeds LS2 9JT, UK
| | - Arnold R Cowen
- Division of Medical Physics, University of Leeds, Room 8.001 Worsley Building, Clarendon Way, Leeds LS2 9JT, UK
| | - Stephen M Kengyelics
- Division of Medical Physics, University of Leeds, Room 8.001 Worsley Building, Clarendon Way, Leeds LS2 9JT, UK
| | - Michael Lupton
- Leeds General Infirmary, Great George Street, Leeds LS1 3EX, UK
| | - Janet Moore
- Leeds General Infirmary, Great George Street, Leeds LS1 3EX, UK
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Dodoo-Amoo NA, Saeed K, Mistry D, Khanna SP, Li L, Linfield EH, Davies AG, Cunningham JE. Non-universality of scaling exponents in quantum Hall transitions. J Phys Condens Matter 2014; 26:475801. [PMID: 25351842 DOI: 10.1088/0953-8984/26/47/475801] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
We have investigated experimentally the scaling behaviour of quantum Hall transitions in GaAs/AlGaAs heterostructures of a range of mobility, carrier concentration, and spacer layer width. All three critical scaling exponents γ, κ and p were determined independently for each sample. We measure the localization length exponent to be γ ≈ 2.3, in good agreement with expected predictions from scaling theory, but κ and p are found to possess non-universal values. Results obtained for κ range from κ = 0.16 ± 0.02 to κ = 0.67 ± 0.02, and are found to be Landau level (LL) dependent, whereas p is found to decrease with increasing sample mobility. Our results demonstrate the existence of two transport regimes in the LL conductivity peak; universality is found within the quantum coherent transport regime present in the tails of the conductivity peak, but is absent within the classical transport regime found close to the critical point at the centre of the conductivity peak. We explain these results using a percolation model and show that the critical scaling exponent depends on certain important length scales that correspond to the microscopic description of electron transport in the bulk of a two-dimensional electron system.
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Affiliation(s)
- N A Dodoo-Amoo
- School of Electronic and Electrical Engineering, University of Leeds, Woodhouse Lane, Leeds, LS2 9JT,UK
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Bettinger JC, Davies AG. The role of the BK channel in ethanol response behaviors: evidence from model organism and human studies. Front Physiol 2014; 5:346. [PMID: 25249984 PMCID: PMC4158801 DOI: 10.3389/fphys.2014.00346] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2014] [Accepted: 08/22/2014] [Indexed: 11/30/2022] Open
Abstract
Alcohol abuse is a significant public health problem. Understanding the molecular effects of ethanol is important for the identification of at risk individuals, as well as the development of novel pharmacotherapies. The large conductance calcium sensitive potassium (BK) channel has emerged as an important player in the behavioral response to ethanol in genetic studies in several model organisms and in humans. The BK channel, slo-1, was identified in a forward genetics screen as a major ethanol target in C. elegans for the effects of ethanol on locomotion and egg-laying behaviors. Regulation of the expression of the BK channel, slo, in Drosophila underlies the development of rapid tolerance to ethanol and benzyl alcohol sedation. Rodent expression studies of the BK-encoding KCNMA1 gene have identified regulation of mRNA levels in response to ethanol exposure, and knock out studies in mice have demonstrated that the β subunits of the BK channel, β1 and β4, can modulate ethanol sensitivity of the channel in electrophysiological preparations, and can influence drinking behavior. In human genetics studies, both KCNMA1 and the genes encoding β subunits of the BK channel have been associated with alcohol dependence. This review describes the genetic data for a role for BK channels in mediating behavioral responses to ethanol across these species.
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Affiliation(s)
- Jill C Bettinger
- Department of Pharmacology and Toxicology, Virginia Commonwealth University Richmond, VA, USA
| | - Andrew G Davies
- Department of Pharmacology and Toxicology, Virginia Commonwealth University Richmond, VA, USA
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Raabe RC, Mathies LD, Davies AG, Bettinger JC. The omega-3 fatty acid eicosapentaenoic acid is required for normal alcohol response behaviors in C. elegans. PLoS One 2014; 9:e105999. [PMID: 25162400 PMCID: PMC4146551 DOI: 10.1371/journal.pone.0105999] [Citation(s) in RCA: 23] [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] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2014] [Accepted: 08/01/2014] [Indexed: 12/18/2022] Open
Abstract
Alcohol addiction is a widespread societal problem, for which there are few treatments. There are significant genetic and environmental influences on abuse liability, and understanding these factors will be important for the identification of susceptible individuals and the development of effective pharmacotherapies. In humans, the level of response to alcohol is strongly predictive of subsequent alcohol abuse. Level of response is a combination of counteracting responses to alcohol, the level of sensitivity to the drug and the degree to which tolerance develops during the drug exposure, called acute functional tolerance. We use the simple and well-characterized nervous system of Caenorhabditis elegans to model the acute behavioral effects of ethanol to identify genetic and environmental factors that influence level of response to ethanol. Given the strong molecular conservation between the neurobiological machinery of worms and humans, cellular-level effects of ethanol are likely to be conserved. Increasingly, variation in long-chain polyunsaturated fatty acid levels has been implicated in complex neurobiological phenotypes in humans, and we recently found that fatty acid levels modify ethanol responses in worms. Here, we report that 1) eicosapentaenoic acid, an omega-3 polyunsaturated fatty acid, is required for the development of acute functional tolerance, 2) dietary supplementation of eicosapentaenoic acid is sufficient for acute tolerance, and 3) dietary eicosapentaenoic acid can alter the wild-type response to ethanol. These results suggest that genetic variation influencing long-chain polyunsaturated fatty acid levels may be important abuse liability loci, and that dietary polyunsaturated fatty acids may be an important environmental modulator of the behavioral response to ethanol.
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Affiliation(s)
- Richard C. Raabe
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, Virginia, United States of America
| | - Laura D. Mathies
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, Virginia, United States of America
| | - Andrew G. Davies
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, Virginia, United States of America
- VCU-Alcohol Research Center, Virginia Commonwealth University, Richmond, Virginia, United States of America
| | - Jill C. Bettinger
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, Virginia, United States of America
- VCU-Alcohol Research Center, Virginia Commonwealth University, Richmond, Virginia, United States of America
- * E-mail:
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Halioua Y, Xu G, Moumdji S, Li LH, Davies AG, Linfield EH, Colombelli R. THz quantum cascade lasers operating on the radiative modes of a 2D photonic crystal. Opt Lett 2014; 39:3962-3965. [PMID: 24978782 DOI: 10.1364/ol.39.003962] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Photonic-crystal lasers operating on Γ-point band-edge states of a photonic structure naturally exploit the so-called "nonradiative" modes. As the surface output coupling efficiency of these modes is low, they have relatively high Q factors, which favor lasing. We propose a new 2D photonic-crystal design that is capable of reversing this mode competition and achieving lasing on the radiative modes instead. Previously, this has only been shown in 1D structures, where the central idea is to introduce anisotropy into the system, both at unit-cell and resonator scales. By applying this concept to 2D photonic-crystal patterned terahertz frequency quantum cascade lasers, surface-emitting devices with diffraction-limited beams are demonstrated, with 17 mW peak output power.
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Lui HS, Taimre T, Bertling K, Lim YL, Dean P, Khanna SP, Lachab M, Valavanis A, Indjin D, Linfield EH, Davies AG, Rakić AD. Terahertz inverse synthetic aperture radar imaging using self-mixing interferometry with a quantum cascade laser. Opt Lett 2014; 39:2629-2632. [PMID: 24784063 DOI: 10.1364/ol.39.002629] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
We propose a terahertz (THz)-frequency synthetic aperture radar imaging technique based on self-mixing (SM) interferometry, using a quantum cascade laser. A signal processing method is employed which extracts and exploits the radar-related information contained in the SM signals, enabling the creation of THz images with improved spatial resolution. We demonstrate this by imaging a standard resolution test target, achieving resolution beyond the diffraction limit.
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Jones MA, Amr S, Ferebee A, Huynh P, Rosenfeld JA, Miles MF, Davies AG, Korey CA, Warrick JM, Shiang R, Elsea SH, Girirajan S, Grotewiel M. Genetic studies in Drosophila and humans support a model for the concerted function of CISD2, PPT1 and CLN3 in disease. Biol Open 2014; 3:342-52. [PMID: 24705017 PMCID: PMC4021356 DOI: 10.1242/bio.20147559] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [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] [Indexed: 01/17/2023] Open
Abstract
Wolfram syndrome (WFS) is a progressive neurodegenerative disease characterized by diabetes insipidus, diabetes mellitus, optic atrophy, and deafness. WFS1 and WFS2 are caused by recessive mutations in the genes Wolfram Syndrome 1 (WFS1) and CDGSH iron sulfur domain 2 (CISD2), respectively. To explore the function of CISD2, we performed genetic studies in flies with altered expression of its Drosophila orthologue, cisd2. Surprisingly, flies with strong ubiquitous RNAi-mediated knockdown of cisd2 had no obvious signs of altered life span, stress resistance, locomotor behavior or several other phenotypes. We subsequently found in a targeted genetic screen, however, that altered function of cisd2 modified the effects of overexpressing the fly orthologues of two lysosomal storage disease genes, palmitoyl-protein thioesterase 1 (PPT1 in humans, Ppt1 in flies) and ceroid-lipofuscinosis, neuronal 3 (CLN3 in humans, cln3 in flies), on eye morphology in flies. We also found that cln3 modified the effects of overexpressing Ppt1 in the eye and that overexpression of cln3 interacted with a loss of function mutation in cisd2 to disrupt locomotor ability in flies. Follow-up multi-species bioinformatic analyses suggested that a gene network centered on CISD2, PPT1 and CLN3 might impact disease through altered carbohydrate metabolism, protein folding and endopeptidase activity. Human genetic studies indicated that copy number variants (duplications and deletions) including CLN3, and possibly another gene in the CISD2/PPT1/CLN3 network, are over-represented in individuals with developmental delay. Our studies indicate that cisd2, Ppt1 and cln3 function in concert in flies, suggesting that CISD2, PPT1 and CLN3 might also function coordinately in humans. Further, our studies raise the possibility that WFS2 and some lysosomal storage disorders might be influenced by common mechanisms and that the underlying genes might have previously unappreciated effects on developmental delay.
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Affiliation(s)
- Melanie A Jones
- Department of Human and Molecular Genetics, Virginia Commonwealth University, Richmond, VA 23298, USA
| | - Sami Amr
- Department of Human and Molecular Genetics, Virginia Commonwealth University, Richmond, VA 23298, USA Molecular Biology and Genetics Program, Virginia Commonwealth University, Richmond, VA 23298, USA
| | - Aerial Ferebee
- Department of Human and Molecular Genetics, Virginia Commonwealth University, Richmond, VA 23298, USA
| | - Phung Huynh
- Department of Human and Molecular Genetics, Virginia Commonwealth University, Richmond, VA 23298, USA
| | | | - Michael F Miles
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, VA 23298, USA
| | - Andrew G Davies
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, VA 23298, USA
| | | | - John M Warrick
- Department of Biology, University of Richmond, Richmond, VA 23173, USA
| | - Rita Shiang
- Department of Human and Molecular Genetics, Virginia Commonwealth University, Richmond, VA 23298, USA
| | - Sarah H Elsea
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Santhosh Girirajan
- Department of Biochemistry and Molecular Biology, Pennsylvania State University, University Park, PA 16802, USA Department of Anthropology, Pennsylvania State University, University Park, PA 16802, USA
| | - Mike Grotewiel
- Department of Human and Molecular Genetics, Virginia Commonwealth University, Richmond, VA 23298, USA Molecular Biology and Genetics Program, Virginia Commonwealth University, Richmond, VA 23298, USA
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