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Gray MD, Spiers L, Coussios CC. Sound speed and attenuation of human pancreas and pancreatic tumors and their influence on focused ultrasound thermal and mechanical therapies. Med Phys 2024; 51:809-825. [PMID: 37477551 DOI: 10.1002/mp.16622] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2022] [Revised: 06/06/2023] [Accepted: 06/20/2023] [Indexed: 07/22/2023] Open
Abstract
BACKGROUND There is increasing interest in using ultrasound for thermal ablation, histotripsy, and thermal or cavitational enhancement of drug delivery for the treatment of pancreatic cancer. Ultrasonic and thermal modelling conducted as part of the treatment planning process requires acoustic property values for all constituent tissues, but the literature contains no data for the human pancreas. PURPOSE This study presents the first acoustic property measurements of human pancreatic samples and provides examples of how these properties impact a broad range of ultrasound therapies. METHODS Data were collected on human pancreatic tissue samples at physiological temperature from 23 consented patients in cooperation with a hospital pathology laboratory. Propagation of ultrasound over the 2.1-4.5 MHz frequency range through samples of various thicknesses and pathologies was measured using a set of custom-built ultrasonic calipers, with the data processed to estimate sound speed and attenuation. The results were used in acoustic and thermal simulations to illustrate the impacts on extracorporeal ultrasound therapies for mild hyperthermia, thermal ablation, and histotripsy implemented with a CE-marked clinical system operating at 0.96 MHz. RESULTS The mean sound speed and attenuation coefficient values for human samples were well below the range of values in the literature for non-human pancreata, while the human attenuation power law exponents were substantially higher. The simulated impacts on ultrasound mediated therapies for the pancreas indicated that when using the human data instead of the literature average, there was a 30% reduction in median temperature elevation in the treatment volume for mild hyperthermia and 43% smaller volume within a 60°C contour for thermal ablation, all driven by attenuation. By comparison, impacts on boiling and intrinsic threshold histotripsy were minor, with peak pressures changing by less than 15% (positive) and 1% (negative) as a consequence of the counteracting effects of attenuation and sound speed. CONCLUSION This study provides the most complete set of speed of sound and attenuation data available for the human pancreas, and it reiterates the importance of acoustic material properties in the planning and conduct of ultrasound-mediated procedures, particularly thermal therapies.
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Affiliation(s)
- Michael D Gray
- Institute of Biomedical Engineering, University of Oxford, Oxford, UK
| | - Laura Spiers
- Institute of Biomedical Engineering, University of Oxford, Oxford, UK
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Brans V, Gray MD, Sezgin E, Stride EPJ. Protein-Decorated Microbubbles for Ultrasound-Mediated Cell Surface Manipulation. ACS Appl Bio Mater 2023; 6:5746-5758. [PMID: 38048163 PMCID: PMC10731656 DOI: 10.1021/acsabm.3c00861] [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] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2023] [Revised: 11/14/2023] [Accepted: 11/20/2023] [Indexed: 12/06/2023]
Abstract
Delivering cargo to the cell membranes of specific cell types in the body is a major challenge for a range of treatments, including immunotherapy. This study investigates employing protein-decorated microbubbles (MBs) and ultrasound (US) to "tag" cellular membranes of interest with a specific protein. Phospholipid-coated MBs were produced and functionalized with a model protein using a metallochelating complex through an NTA(Ni) and histidine residue interaction. Successful "tagging" of the cellular membrane was observed using microscopy in adherent cells and was promoted by US exposure. Further modification of the MB surface to enable selective binding to target cells was then achieved by functionalizing the MBs with a targeting protein (transferrin) that specifically binds to a receptor on the target cell membrane. Attachment and subsequent transfer of material from MBs functionalized with transferrin to the target cells significantly increased, even in the absence of US. This work demonstrates the potential of these MBs as a platform for the noninvasive delivery of proteins to the surface of specific cell types.
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Affiliation(s)
- Veerle
A. Brans
- Department
of Engineering Science, Institute of Biomedical Engineering, University of Oxford, Oxford OX3 7DL, U.K.
| | - Michael D. Gray
- Department
of Engineering Science, Institute of Biomedical Engineering, University of Oxford, Oxford OX3 7DL, U.K.
| | - Erdinc Sezgin
- Science
for Life Laboratory, Department of Women’s and Children’s
Health, Karolinska Institutet, 17165 Solna, Sweden
| | - Eleanor P. J. Stride
- Department
of Engineering Science, Institute of Biomedical Engineering, University of Oxford, Oxford OX3 7DL, U.K.
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Gray MD, Coussios CC. PAX (Passive-Active Crossing) Method for Sub-Millimeter Coregistration of Passive Acoustic Mapping and B-Mode Images. IEEE Trans Ultrason Ferroelectr Freq Control 2022; 69:3179-3189. [PMID: 36112556 DOI: 10.1109/tuffc.2022.3207327] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Nonlinear ultrasonic emissions produced during a therapeutic ultrasound procedure can be detected, localized, and quantified through a class of methods that can be referred to as passive acoustic mapping (PAM). While a variety of PAM beamforming algorithms may be employed, they share a common limitation that a single sound speed is specified for both phase steering of array elements and for calculation of source power or energy. The specified value may be inadequate whether derived from B-mode-based metrics or literature values for constituent materials. This study employed experiments and simulations with linear and curvilinear array geometries to investigate the impact of in situ sound speed uncertainties on source localization in layered media. The data were also used to evaluate a new method for optimizing coregistration of PAM and B-mode images. Coregistration errors as large as 10 mm were observed with the curvilinear array, which also showed much greater sound speed sensitivity than the linear array. Errors with both array geometries were typically reduced to the order of 0.1 mm using the proposed optimization method regardless of beamformer choice or whether the array was calibrated. In a further step toward reliable implementation of PAM, the current work provides an approach that can help ensure that therapeutic ultrasound procedures are accurately guided by cavitation emissions.
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Jones IT, D Gray M, Mooney TA. Soundscapes as heard by invertebrates and fishes: Particle motion measurements on coral reefs. J Acoust Soc Am 2022; 152:399. [PMID: 35931548 DOI: 10.1121/10.0012579] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/08/2022] [Accepted: 06/24/2022] [Indexed: 06/15/2023]
Abstract
Coral reef soundscapes are increasingly studied for their ecological uses by invertebrates and fishes, for monitoring habitat quality, and to investigate effects of anthropogenic noise pollution. Few examinations of aquatic soundscapes have reported particle motion levels and variability, despite their relevance to invertebrates and fishes. In this study, ambient particle acceleration was quantified from orthogonal hydrophone arrays over several months at four coral reef sites, which varied in benthic habitat and fish communities. Time-averaged particle acceleration magnitudes were similar across axes, within 3 dB. Temporal trends of particle acceleration corresponded with those of sound pressure, and the strength of diel trends in both metrics significantly correlated with percent coral cover. Higher magnitude particle accelerations diverged further from pressure values, potentially representing sounds recorded in the near field. Particle acceleration levels were also reported for boat and example fish sounds. Comparisons with particle acceleration derived audiograms suggest the greatest capacity of invertebrates and fishes to detect soundscape components below 100 Hz, and poorer detectability of soundscapes by invertebrates compared to fishes. Based on these results, research foci are discussed for which reporting of particle motion is essential, versus those for which sound pressure may suffice.
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Affiliation(s)
- Ian T Jones
- Biology Department, Woods Hole Oceanographic Institution, 266 Woods Hole Road, Woods Hole, Massachusetts 02543, USA
| | - Michael D Gray
- Institute of Biomedical Engineering, University of Oxford, Oxford, OX3 7LD, United Kingdom
| | - T Aran Mooney
- Biology Department, Woods Hole Oceanographic Institution, 266 Woods Hole Road, Woods Hole, Massachusetts 02543, USA
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Ruan JL, Browning RJ, Yildiz YO, Bau L, Kamila S, Gray MD, Folkes L, Hampson A, McHale AP, Callan JF, Vojnovic B, Kiltie AE, Stride E. Evaluation of Loading Strategies to Improve Tumor Uptake of Gemcitabine in a Murine Orthotopic Bladder Cancer Model Using Ultrasound and Microbubbles. Ultrasound Med Biol 2021; 47:1596-1615. [PMID: 33707089 DOI: 10.1016/j.ultrasmedbio.2021.02.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/18/2020] [Revised: 02/01/2021] [Accepted: 02/02/2021] [Indexed: 06/12/2023]
Abstract
In this study we compared three different microbubble-based approaches to the delivery of a widely used chemotherapy drug, gemcitabine: (i) co-administration of gemcitabine and microbubbles (Gem+MB); (ii) conjugates of microbubbles and gemcitabine-loaded liposomes (GemlipoMB); and (iii) microbubbles with gemcitabine directly bound to their surfaces (GembioMB). Both in vitro and in vivo investigations were carried out, respectively, in the RT112 bladder cancer cell line and in a murine orthotopic muscle-invasive bladder cancer model. The in vitro (in vivo) ultrasound exposure conditions were a 1 (1.1) MHz centre frequency, 0.07 (1.0) MPa peak negative pressure, 3000 (20,000) cycles and 100 (0.5) Hz pulse repetition frequency. Ultrasound exposure produced no significant increase in drug uptake either in vitro or in vivo compared with the drug-only control for co-administered gemcitabine and microbubbles. In vivo, GemlipoMB prolonged the plasma circulation time of gemcitabine, but only GembioMB produced a statistically significant increase in cleaved caspase 3 expression in the tumor, indicative of gemcitabine-induced apoptosis.
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Affiliation(s)
- Jia-Ling Ruan
- MRC Oxford Institute for Radiation Oncology, Department of Oncology, University of Oxford, Oxford, United Kingdom
| | - Richard J Browning
- Institute of Biomedical Engineering, University of Oxford, Oxford, United Kingdom
| | - Yesna O Yildiz
- MRC Oxford Institute for Radiation Oncology, Department of Oncology, University of Oxford, Oxford, United Kingdom
| | - Luca Bau
- Institute of Biomedical Engineering, University of Oxford, Oxford, United Kingdom
| | - Sukanta Kamila
- Biomedical Sciences Research Institute, University of Ulster, Coleraine, Northern Ireland, United Kingdom
| | - Michael D Gray
- Institute of Biomedical Engineering, University of Oxford, Oxford, United Kingdom
| | - Lisa Folkes
- MRC Oxford Institute for Radiation Oncology, Department of Oncology, University of Oxford, Oxford, United Kingdom
| | - Alix Hampson
- MRC Oxford Institute for Radiation Oncology, Department of Oncology, University of Oxford, Oxford, United Kingdom
| | - Anthony P McHale
- Biomedical Sciences Research Institute, University of Ulster, Coleraine, Northern Ireland, United Kingdom
| | - John F Callan
- Biomedical Sciences Research Institute, University of Ulster, Coleraine, Northern Ireland, United Kingdom
| | - Borivoj Vojnovic
- MRC Oxford Institute for Radiation Oncology, Department of Oncology, University of Oxford, Oxford, United Kingdom
| | - Anne E Kiltie
- MRC Oxford Institute for Radiation Oncology, Department of Oncology, University of Oxford, Oxford, United Kingdom
| | - Eleanor Stride
- Institute of Biomedical Engineering, University of Oxford, Oxford, United Kingdom.
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Gray MD, Elbes D, Paverd C, Lyka E, Coviello CM, Cleveland RO, Coussios CC. Dual-Array Passive Acoustic Mapping for Cavitation Imaging With Enhanced 2-D Resolution. IEEE Trans Ultrason Ferroelectr Freq Control 2021; 68:647-663. [PMID: 32845836 DOI: 10.1109/tuffc.2020.3019573] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Passive acoustic mapping (PAM) techniques have been developed for the purposes of detecting, localizing, and quantifying cavitation activity during therapeutic ultrasound procedures. Implementation with conventional diagnostic ultrasound arrays has allowed planar mapping of bubble acoustic emissions to be overlaid with B-mode anatomical images, with a variety of beamforming approaches providing enhanced resolution at the cost of extended computation times. However, no passive signal processing techniques implemented to date have overcome the fundamental physical limitation of the conventional diagnostic array aperture that results in point spread functions with axial/lateral beamwidth ratios of nearly an order of magnitude. To mitigate this problem, the use of a pair of orthogonally oriented diagnostic arrays was recently proposed, with potential benefits arising from the substantially expanded range of observation angles. This article presents experiments and simulations intended to demonstrate the performance and limitations of the dual-array system concept. The key finding of this study is that source pair resolution of better than 1 mm is now possible in both dimensions of the imaging plane using a pair of 7.5-MHz center frequency conventional arrays at a distance of 7.6cm. With an eye toward accelerating computations for real-time applications, channel count reductions of up to a factor of eight induce negligible performance losses. Modest sensitivities to sound speed and relative array position uncertainties were identified, but if these can be kept on the order of 1% and 1 mm, respectively, then the proposed methods offer the potential for a step improvement in cavitation monitoring capability.
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Gray MD, Coussios CC. Compensation of array lens effects for improved co-registration of passive acoustic mapping and B-mode images for cavitation monitoring. J Acoust Soc Am 2019; 146. [PMID: 31370617 PMCID: PMC7080234 DOI: 10.1121/1.5118238#suppl] [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] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
Passive acoustic mapping (PAM) techniques offer a simple means of spatio-temporal cavitation monitoring during therapeutic ultrasound procedures. Implementation with a conventional diagnostic ultrasound system allows natural integration of PAM with B-mode imaging. However, the refracting properties of diagnostic array lenses may introduce PAM image registration errors that could lead to inaccuracies in treatment monitoring and guidance. To address these concerns, this paper presents lens characterization of two different array designs, analytical estimation of lens-induced source mapping errors in simple media, and experimental demonstration and correction of lens effects, reducing the depth-averaged image co-registration errors to no more than 0.52 mm.
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Affiliation(s)
- Michael D Gray
- Institute of Biomedical Engineering, Department of Engineering Science, University of Oxford, Old Road Campus Research Building, Oxford, OX3 7DQ, United ,
| | - Constantin C Coussios
- Institute of Biomedical Engineering, Department of Engineering Science, University of Oxford, Old Road Campus Research Building, Oxford, OX3 7DQ, United ,
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Gray MD, Coussios CC. Compensation of array lens effects for improved co-registration of passive acoustic mapping and B-mode images for cavitation monitoring. J Acoust Soc Am 2019; 146:EL78. [PMID: 31370617 PMCID: PMC7080234 DOI: 10.1121/1.5118238] [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] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Passive acoustic mapping (PAM) techniques offer a simple means of spatio-temporal cavitation monitoring during therapeutic ultrasound procedures. Implementation with a conventional diagnostic ultrasound system allows natural integration of PAM with B-mode imaging. However, the refracting properties of diagnostic array lenses may introduce PAM image registration errors that could lead to inaccuracies in treatment monitoring and guidance. To address these concerns, this paper presents lens characterization of two different array designs, analytical estimation of lens-induced source mapping errors in simple media, and experimental demonstration and correction of lens effects, reducing the depth-averaged image co-registration errors to no more than 0.52 mm.
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Affiliation(s)
- Michael D Gray
- Institute of Biomedical Engineering, Department of Engineering Science, University of Oxford, Old Road Campus Research Building, Oxford, OX3 7DQ, United ,
| | - Constantin C Coussios
- Institute of Biomedical Engineering, Department of Engineering Science, University of Oxford, Old Road Campus Research Building, Oxford, OX3 7DQ, United ,
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Gray MD, Lyon PC, Mannaris C, Folkes LK, Stratford M, Campo L, Chung DYF, Scott S, Anderson M, Goldin R, Carlisle R, Wu F, Middleton MR, Gleeson FV, Coussios CC. Focused Ultrasound Hyperthermia for Targeted Drug Release from Thermosensitive Liposomes: Results from a Phase I Trial. Radiology 2019; 291:232-238. [PMID: 30644817 DOI: 10.1148/radiol.2018181445] [Citation(s) in RCA: 55] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Purpose To demonstrate the feasibility and safety of using focused ultrasound planning models to determine the treatment parameters needed to deliver volumetric mild hyperthermia for targeted drug delivery without real-time thermometry. Materials and Methods This study was part of the Targeted Doxorubicin, or TARDOX, phase I prospective trial of focused ultrasound-mediated, hyperthermia-triggered drug delivery to solid liver tumors ( ClinicalTrials.gov identifier NCT02181075). Ten participants (age range, 49-68 years; average age, 60 years; four women) were treated from March 2015 to March 2017 by using a clinically approved focused ultrasound system to release doxorubicin from lyso-thermosensitive liposomes. Ultrasonic heating of target tumors (treated volume: 11-73 cm3 [mean ± standard deviation, 50 cm3 ± 26]) was monitored in six participants by using a minimally invasive temperature sensor; four participants were treated without real-time thermometry. For all participants, CT images were used with a patient-specific hyperthermia model to define focused ultrasound treatment plans. Feasibility was assessed by comparing model-prescribed focused ultrasound powers to those implemented for treatment. Safety was assessed by evaluating MR images and biopsy specimens for evidence of thermal ablation and monitoring adverse events. Results The mean difference between predicted and implemented treatment powers was -0.1 W ± 17.7 (n = 10). No evidence of focused ultrasound-related adverse effects, including thermal ablation, was found. Conclusion In this 10-participant study, the authors confirmed the feasibility of using focused ultrasound-mediated hyperthermia planning models to define treatment parameters that safely enabled targeted, noninvasive drug delivery to liver tumors while monitored with B-mode guidance and without real-time thermometry. Published under a CC BY 4.0 license. Online supplemental material is available for this article. See also the editorial by Dickey and Levi-Polyachenko in this issue.
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Affiliation(s)
- Michael D Gray
- From the Institute of Biomedical Engineering, University of Oxford, Old Road Campus Research Building, Oxford OX3 7DQ, England (M.D.G., P.C.L., C.M., R.C., C.C.C.); Nuffield Department of Surgical Sciences, John Radcliffe Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford, England (P.C.L., F.W.); Departments of Radiology (P.C.L., D.Y.F.C., M.A., F.V.G.) and Oncology (M.R.M.), Churchill Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford, England; Department of Oncology, CRUK/MRC Oxford Institute for Radiation Oncology, University of Oxford, Oxford, England (L.K.F., M.S., L.C.); Nuffield Department of Anaesthetics, Oxford University Hospitals Foundation NHS Trust, Oxford, England (S.S.); and Centre for Pathology, Faculty of Medicine, Imperial College London, London, England (R.G.)
| | - Paul C Lyon
- From the Institute of Biomedical Engineering, University of Oxford, Old Road Campus Research Building, Oxford OX3 7DQ, England (M.D.G., P.C.L., C.M., R.C., C.C.C.); Nuffield Department of Surgical Sciences, John Radcliffe Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford, England (P.C.L., F.W.); Departments of Radiology (P.C.L., D.Y.F.C., M.A., F.V.G.) and Oncology (M.R.M.), Churchill Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford, England; Department of Oncology, CRUK/MRC Oxford Institute for Radiation Oncology, University of Oxford, Oxford, England (L.K.F., M.S., L.C.); Nuffield Department of Anaesthetics, Oxford University Hospitals Foundation NHS Trust, Oxford, England (S.S.); and Centre for Pathology, Faculty of Medicine, Imperial College London, London, England (R.G.)
| | - Christophoros Mannaris
- From the Institute of Biomedical Engineering, University of Oxford, Old Road Campus Research Building, Oxford OX3 7DQ, England (M.D.G., P.C.L., C.M., R.C., C.C.C.); Nuffield Department of Surgical Sciences, John Radcliffe Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford, England (P.C.L., F.W.); Departments of Radiology (P.C.L., D.Y.F.C., M.A., F.V.G.) and Oncology (M.R.M.), Churchill Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford, England; Department of Oncology, CRUK/MRC Oxford Institute for Radiation Oncology, University of Oxford, Oxford, England (L.K.F., M.S., L.C.); Nuffield Department of Anaesthetics, Oxford University Hospitals Foundation NHS Trust, Oxford, England (S.S.); and Centre for Pathology, Faculty of Medicine, Imperial College London, London, England (R.G.)
| | - Lisa K Folkes
- From the Institute of Biomedical Engineering, University of Oxford, Old Road Campus Research Building, Oxford OX3 7DQ, England (M.D.G., P.C.L., C.M., R.C., C.C.C.); Nuffield Department of Surgical Sciences, John Radcliffe Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford, England (P.C.L., F.W.); Departments of Radiology (P.C.L., D.Y.F.C., M.A., F.V.G.) and Oncology (M.R.M.), Churchill Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford, England; Department of Oncology, CRUK/MRC Oxford Institute for Radiation Oncology, University of Oxford, Oxford, England (L.K.F., M.S., L.C.); Nuffield Department of Anaesthetics, Oxford University Hospitals Foundation NHS Trust, Oxford, England (S.S.); and Centre for Pathology, Faculty of Medicine, Imperial College London, London, England (R.G.)
| | - Michael Stratford
- From the Institute of Biomedical Engineering, University of Oxford, Old Road Campus Research Building, Oxford OX3 7DQ, England (M.D.G., P.C.L., C.M., R.C., C.C.C.); Nuffield Department of Surgical Sciences, John Radcliffe Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford, England (P.C.L., F.W.); Departments of Radiology (P.C.L., D.Y.F.C., M.A., F.V.G.) and Oncology (M.R.M.), Churchill Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford, England; Department of Oncology, CRUK/MRC Oxford Institute for Radiation Oncology, University of Oxford, Oxford, England (L.K.F., M.S., L.C.); Nuffield Department of Anaesthetics, Oxford University Hospitals Foundation NHS Trust, Oxford, England (S.S.); and Centre for Pathology, Faculty of Medicine, Imperial College London, London, England (R.G.)
| | - Leticia Campo
- From the Institute of Biomedical Engineering, University of Oxford, Old Road Campus Research Building, Oxford OX3 7DQ, England (M.D.G., P.C.L., C.M., R.C., C.C.C.); Nuffield Department of Surgical Sciences, John Radcliffe Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford, England (P.C.L., F.W.); Departments of Radiology (P.C.L., D.Y.F.C., M.A., F.V.G.) and Oncology (M.R.M.), Churchill Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford, England; Department of Oncology, CRUK/MRC Oxford Institute for Radiation Oncology, University of Oxford, Oxford, England (L.K.F., M.S., L.C.); Nuffield Department of Anaesthetics, Oxford University Hospitals Foundation NHS Trust, Oxford, England (S.S.); and Centre for Pathology, Faculty of Medicine, Imperial College London, London, England (R.G.)
| | - Daniel Y F Chung
- From the Institute of Biomedical Engineering, University of Oxford, Old Road Campus Research Building, Oxford OX3 7DQ, England (M.D.G., P.C.L., C.M., R.C., C.C.C.); Nuffield Department of Surgical Sciences, John Radcliffe Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford, England (P.C.L., F.W.); Departments of Radiology (P.C.L., D.Y.F.C., M.A., F.V.G.) and Oncology (M.R.M.), Churchill Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford, England; Department of Oncology, CRUK/MRC Oxford Institute for Radiation Oncology, University of Oxford, Oxford, England (L.K.F., M.S., L.C.); Nuffield Department of Anaesthetics, Oxford University Hospitals Foundation NHS Trust, Oxford, England (S.S.); and Centre for Pathology, Faculty of Medicine, Imperial College London, London, England (R.G.)
| | - Shaun Scott
- From the Institute of Biomedical Engineering, University of Oxford, Old Road Campus Research Building, Oxford OX3 7DQ, England (M.D.G., P.C.L., C.M., R.C., C.C.C.); Nuffield Department of Surgical Sciences, John Radcliffe Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford, England (P.C.L., F.W.); Departments of Radiology (P.C.L., D.Y.F.C., M.A., F.V.G.) and Oncology (M.R.M.), Churchill Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford, England; Department of Oncology, CRUK/MRC Oxford Institute for Radiation Oncology, University of Oxford, Oxford, England (L.K.F., M.S., L.C.); Nuffield Department of Anaesthetics, Oxford University Hospitals Foundation NHS Trust, Oxford, England (S.S.); and Centre for Pathology, Faculty of Medicine, Imperial College London, London, England (R.G.)
| | - Mark Anderson
- From the Institute of Biomedical Engineering, University of Oxford, Old Road Campus Research Building, Oxford OX3 7DQ, England (M.D.G., P.C.L., C.M., R.C., C.C.C.); Nuffield Department of Surgical Sciences, John Radcliffe Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford, England (P.C.L., F.W.); Departments of Radiology (P.C.L., D.Y.F.C., M.A., F.V.G.) and Oncology (M.R.M.), Churchill Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford, England; Department of Oncology, CRUK/MRC Oxford Institute for Radiation Oncology, University of Oxford, Oxford, England (L.K.F., M.S., L.C.); Nuffield Department of Anaesthetics, Oxford University Hospitals Foundation NHS Trust, Oxford, England (S.S.); and Centre for Pathology, Faculty of Medicine, Imperial College London, London, England (R.G.)
| | - Robert Goldin
- From the Institute of Biomedical Engineering, University of Oxford, Old Road Campus Research Building, Oxford OX3 7DQ, England (M.D.G., P.C.L., C.M., R.C., C.C.C.); Nuffield Department of Surgical Sciences, John Radcliffe Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford, England (P.C.L., F.W.); Departments of Radiology (P.C.L., D.Y.F.C., M.A., F.V.G.) and Oncology (M.R.M.), Churchill Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford, England; Department of Oncology, CRUK/MRC Oxford Institute for Radiation Oncology, University of Oxford, Oxford, England (L.K.F., M.S., L.C.); Nuffield Department of Anaesthetics, Oxford University Hospitals Foundation NHS Trust, Oxford, England (S.S.); and Centre for Pathology, Faculty of Medicine, Imperial College London, London, England (R.G.)
| | - Robert Carlisle
- From the Institute of Biomedical Engineering, University of Oxford, Old Road Campus Research Building, Oxford OX3 7DQ, England (M.D.G., P.C.L., C.M., R.C., C.C.C.); Nuffield Department of Surgical Sciences, John Radcliffe Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford, England (P.C.L., F.W.); Departments of Radiology (P.C.L., D.Y.F.C., M.A., F.V.G.) and Oncology (M.R.M.), Churchill Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford, England; Department of Oncology, CRUK/MRC Oxford Institute for Radiation Oncology, University of Oxford, Oxford, England (L.K.F., M.S., L.C.); Nuffield Department of Anaesthetics, Oxford University Hospitals Foundation NHS Trust, Oxford, England (S.S.); and Centre for Pathology, Faculty of Medicine, Imperial College London, London, England (R.G.)
| | - Feng Wu
- From the Institute of Biomedical Engineering, University of Oxford, Old Road Campus Research Building, Oxford OX3 7DQ, England (M.D.G., P.C.L., C.M., R.C., C.C.C.); Nuffield Department of Surgical Sciences, John Radcliffe Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford, England (P.C.L., F.W.); Departments of Radiology (P.C.L., D.Y.F.C., M.A., F.V.G.) and Oncology (M.R.M.), Churchill Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford, England; Department of Oncology, CRUK/MRC Oxford Institute for Radiation Oncology, University of Oxford, Oxford, England (L.K.F., M.S., L.C.); Nuffield Department of Anaesthetics, Oxford University Hospitals Foundation NHS Trust, Oxford, England (S.S.); and Centre for Pathology, Faculty of Medicine, Imperial College London, London, England (R.G.)
| | - Mark R Middleton
- From the Institute of Biomedical Engineering, University of Oxford, Old Road Campus Research Building, Oxford OX3 7DQ, England (M.D.G., P.C.L., C.M., R.C., C.C.C.); Nuffield Department of Surgical Sciences, John Radcliffe Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford, England (P.C.L., F.W.); Departments of Radiology (P.C.L., D.Y.F.C., M.A., F.V.G.) and Oncology (M.R.M.), Churchill Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford, England; Department of Oncology, CRUK/MRC Oxford Institute for Radiation Oncology, University of Oxford, Oxford, England (L.K.F., M.S., L.C.); Nuffield Department of Anaesthetics, Oxford University Hospitals Foundation NHS Trust, Oxford, England (S.S.); and Centre for Pathology, Faculty of Medicine, Imperial College London, London, England (R.G.)
| | - Fergus V Gleeson
- From the Institute of Biomedical Engineering, University of Oxford, Old Road Campus Research Building, Oxford OX3 7DQ, England (M.D.G., P.C.L., C.M., R.C., C.C.C.); Nuffield Department of Surgical Sciences, John Radcliffe Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford, England (P.C.L., F.W.); Departments of Radiology (P.C.L., D.Y.F.C., M.A., F.V.G.) and Oncology (M.R.M.), Churchill Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford, England; Department of Oncology, CRUK/MRC Oxford Institute for Radiation Oncology, University of Oxford, Oxford, England (L.K.F., M.S., L.C.); Nuffield Department of Anaesthetics, Oxford University Hospitals Foundation NHS Trust, Oxford, England (S.S.); and Centre for Pathology, Faculty of Medicine, Imperial College London, London, England (R.G.)
| | - Constantin C Coussios
- From the Institute of Biomedical Engineering, University of Oxford, Old Road Campus Research Building, Oxford OX3 7DQ, England (M.D.G., P.C.L., C.M., R.C., C.C.C.); Nuffield Department of Surgical Sciences, John Radcliffe Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford, England (P.C.L., F.W.); Departments of Radiology (P.C.L., D.Y.F.C., M.A., F.V.G.) and Oncology (M.R.M.), Churchill Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford, England; Department of Oncology, CRUK/MRC Oxford Institute for Radiation Oncology, University of Oxford, Oxford, England (L.K.F., M.S., L.C.); Nuffield Department of Anaesthetics, Oxford University Hospitals Foundation NHS Trust, Oxford, England (S.S.); and Centre for Pathology, Faculty of Medicine, Imperial College London, London, England (R.G.)
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Lyka E, Coviello CM, Paverd C, Gray MD, Coussios CC. Passive Acoustic Mapping Using Data-Adaptive Beamforming Based on Higher Order Statistics. IEEE Trans Med Imaging 2018; 37:2582-2592. [PMID: 29994701 DOI: 10.1109/tmi.2018.2843291] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
Sources of nonlinear acoustic emissions, particularly those associated with cavitation activity, play a key role in the safety and efficacy of current and emerging therapeutic ultrasound applications, such as oncological drug delivery, blood-brain barrier opening, and histotripsy. Passive acoustic mapping (PAM) is the first technique to enable real-time and non-invasive imaging of cavitation activity during therapeutic ultrasound exposure, through the recording and passive beamforming of broadband acoustic emissions using an array of ultrasound detectors. Initial limitations in PAM spatial resolution led to the adoption of optimal data-adaptive beamforming algorithms, such as the robust capon beamformer (RCB), that provide improved interference suppression and calibration error mitigation compared to non-adaptive beamformers. However, such approaches are restricted by the assumption that the recorded signals have a Gaussian distribution. To overcome this limitation and further improve the source resolvability of PAM, we propose a new beamforming approach termed robust beamforming by linear programming (RLPB). Along with the variance, this optimization-based method uses higher-order-statistics of the recorded signals, making no prior assumption on the statistical distribution of the acoustic signals. The RLPB is found via numerical simulations to improve resolvability over time exposure acoustics and RCB. In vitro experimentation yielded improved resolvability with respect to the source-to-array distance on the order of 22% axially and 13% transversely relative to RCB, whilst successfully accounting for array calibration errors. The improved resolution and decreased dependence on accurate calibration of RLPB is expected to facilitate the clinical translation of PAM for diagnostic, including super-resolution, and therapeutic ultrasound applications.
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Gray MD, Coussios CC. Broadband Ultrasonic Attenuation Estimation and Compensation With Passive Acoustic Mapping. IEEE Trans Ultrason Ferroelectr Freq Control 2018; 65:1997-2011. [PMID: 30130184 DOI: 10.1109/tuffc.2018.2866171] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
Several active and passive techniques have been developed to detect, localize, and quantify cavitation activity during therapeutic ultrasound procedures. Much of the prior cavitation monitoring research has been conducted using lossless in vitro systems or small animal models in which path attenuation effects were minimal. However, the performance of these techniques may be substantially degraded by attenuation between the internal therapeutic target and the external monitoring system. As a further step toward clinical application of passive acoustic mapping (PAM), this paper presents methods for attenuation estimation and compensation based on broadband cavitation data measured with a linear ultrasound array. Soft tissue phantom experiment results are used to illustrate: 1) the impact of realistic attenuation on PAM; 2) the possibility of estimating attenuation from cavitation data; 3) cavitation source energy estimation following attenuation compensation; and 4) the impact of sound speed uncertainty on PAM-related processing. Cavitation-based estimates of attenuation were within 1.5%-6.2% of the values found from conventional through-transmission measurements. Tissue phantom attenuation reduced the PAM energy estimate by an order of magnitude, but array data compensation using the cavitation-based attenuation spectrum enabled recovery of the PAM energy estimate to within 2.9%-5.9% of the values computed in the absence of the phantom. Sound speed uncertainties were found to modestly impact attenuation-compensated PAM energies, inducing errors no larger than 28% for a 40-m/s path-averaged speed error. Together, the results indicate the potential to significantly enhance the quantitative capabilities of PAM for ensuring therapeutic safety and efficacy.
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Lyon PC, Gray MD, Mannaris C, Folkes LK, Stratford M, Campo L, Chung DYF, Scott S, Anderson M, Goldin R, Carlisle R, Wu F, Middleton MR, Gleeson FV, Coussios CC. Safety and feasibility of ultrasound-triggered targeted drug delivery of doxorubicin from thermosensitive liposomes in liver tumours (TARDOX): a single-centre, open-label, phase 1 trial. Lancet Oncol 2018; 19:1027-1039. [PMID: 30001990 PMCID: PMC6073884 DOI: 10.1016/s1470-2045(18)30332-2] [Citation(s) in RCA: 136] [Impact Index Per Article: 22.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2018] [Revised: 04/18/2018] [Accepted: 04/20/2018] [Indexed: 01/22/2023]
Abstract
BACKGROUND Previous preclinical research has shown that extracorporeal devices can be used to enhance the delivery and distribution of systemically administered anticancer drugs, resulting in increased intratumoural concentrations. We aimed to assess the safety and feasibility of targeted release and enhanced delivery of doxorubicin to solid tumours from thermosensitive liposomes triggered by mild hyperthermia, induced non-invasively by focused ultrasound. METHODS We did an open-label, single-centre, phase 1 trial in a single UK hospital. Adult patients (aged ≥18 years) with unresectable and non-ablatable primary or secondary liver tumours of any histological subtype were considered for the study. Patients received a single intravenous infusion (50 mg/m2) of lyso-thermosensitive liposomal doxorubicin (LTLD), followed by extracorporeal focused ultrasound exposure of a single target liver tumour. The trial had two parts: in part I, patients had a real-time thermometry device implanted intratumourally, whereas patients in part II proceeded without thermometry and we used a patient-specific model to predict optimal exposure parameters. We assessed tumour biopsies obtained before and after focused ultrasound exposure for doxorubicin concentration and distribution. The primary endpoint was at least a doubling of total intratumoural doxorubicin concentration in at least half of the patients treated, on an intention-to-treat basis. This study is registered with ClinicalTrials.gov, number NCT02181075, and is now closed to recruitment. FINDINGS Between March 13, 2015, and March 27, 2017, ten patients were enrolled in the study (six patients in part I and four in part II), and received a dose of LTLD followed by focused ultrasound exposure. The treatment resulted in an average increase of 3·7 times in intratumoural biopsy doxorubicin concentrations, from an estimate of 2·34 μg/g (SD 0·93) immediately after drug infusion to 8·56 μg/g (5·69) after focused ultrasound. Increases of two to ten times were observed in seven (70%) of ten patients, satisfying the primary endpoint. Serious adverse events registered were expected grade 4 transient neutropenia in five patients and prolonged hospital stay due to unexpected grade 1 confusion in one patient. Grade 3-4 adverse events recorded were neutropenia (grade 3 in one patient and grade 4 in five patients), and grade 3 anaemia in one patient. No treatment-related deaths occurred. INTERPRETATION The combined treatment of LTLD and non-invasive focused ultrasound hyperthermia in this study seemed to be clinically feasible, safe, and able to enhance intratumoural drug delivery, providing targeted chemo-ablative response in human liver tumours that were refractory to standard chemotherapy. FUNDING Oxford Biomedical Research Centre, National Institute for Health Research.
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Affiliation(s)
- Paul C Lyon
- Nuffield Department of Surgical Sciences, John Radcliffe Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford, UK; Department of Radiology, Churchill Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford, UK; Institute of Biomedical Engineering, University of Oxford, Oxford, UK
| | - Michael D Gray
- Institute of Biomedical Engineering, University of Oxford, Oxford, UK
| | | | - Lisa K Folkes
- CRUK/MRC Oxford Institute for Radiation Oncology, Department of Oncology, University of Oxford, Oxford, UK
| | - Michael Stratford
- CRUK/MRC Oxford Institute for Radiation Oncology, Department of Oncology, University of Oxford, Oxford, UK
| | - Leticia Campo
- CRUK/MRC Oxford Institute for Radiation Oncology, Department of Oncology, University of Oxford, Oxford, UK
| | - Daniel Y F Chung
- Department of Radiology, Churchill Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford, UK
| | - Shaun Scott
- Nuffield Department of Anaesthetics, John Radcliffe Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford, UK
| | - Mark Anderson
- Department of Radiology, Churchill Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford, UK
| | - Robert Goldin
- Centre for Pathology, Faculty of Medicine, Imperial College London, London, UK
| | - Robert Carlisle
- Institute of Biomedical Engineering, University of Oxford, Oxford, UK
| | - Feng Wu
- Nuffield Department of Surgical Sciences, John Radcliffe Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford, UK
| | - Mark R Middleton
- Department of Oncology, Churchill Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford, UK
| | - Fergus V Gleeson
- Department of Radiology, Churchill Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford, UK
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Holguin SY, Gray MD, Joseph P, Thadhani NN, Prausnitz MR. Photoporation Using Carbon Nanotubes for Intracellular Delivery of Molecules and Its Relationship to Photoacoustic Pressure. Adv Healthc Mater 2018; 7. [PMID: 29205931 DOI: 10.1002/adhm.201701007] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2017] [Indexed: 01/08/2023]
Abstract
Exposure of carbon-black (CB) nanoparticles to near-infrared nanosecond-pulsed laser energy can cause efficient intracellular delivery of molecules by photoporation. Here, cellular bioeffects of multi-walled carbon nanotubes (MWCNTs) and single-walled carbon nanotubes (SWCNTs) are compared to those of CB nanoparticles. In DU145 prostate-cancer cells, photoporation using CB nanoparticles transitions from (i) cells with molecular uptake to (ii) nonviable cells to (iii) fragmented cells with increasing laser fluence, as seen previously. In contrast, photoporation with MWCNTs causes uptake and, at higher fluence, fragmentation, but does not generate nonviable cells, and SWCNTs show little evidence of bioeffects, except at extreme laser conditions, which generate nonviable cells and fragmentation, but no significant uptake. These different behaviors cannot be explained by photoacoustic pressure output from the particles. All particle types emit a single, ≈100 ns, mostly positive-pressure pulse that increases in amplitude with laser fluence. Different particle types emit different peak pressures, which are highest for SWCNTs, followed by CB nanoparticles and then MWCNTs, which does not correlate with cellular bioeffects between different particle types. This study concludes that cellular bioeffects depend strongly on the type of carbon nanoparticle used during photoporation and that photoacoustic pressure is unlikely to play a direct mechanistic role in the observed bioeffects.
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Affiliation(s)
- Stefany Y. Holguin
- School of Materials Science and Engineering Georgia Institute of Technology Atlanta GA 30332 USA
| | - Michael D. Gray
- Institute of BME U. Oxford Chem & Biomolecular Eng, GaTech Oxford OX3 7DQ UK
| | - Princeton Joseph
- Wallace H. Coulter Department of Biomedical Engineering Georgia Institute of Technology Atlanta GA 30332 USA
| | - Naresh N. Thadhani
- School of Materials Science and Engineering Georgia Institute of Technology Atlanta GA 30332 USA
| | - Mark R. Prausnitz
- Wallace H. Coulter Department of Biomedical Engineering Georgia Institute of Technology Atlanta GA 30332 USA
- School of Chemical and Biomolecular Engineering Georgia Institute of Technology Atlanta GA 30332 USA
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Gray MD, Lyka E, Coussios CC. Diffraction Effects and Compensation in Passive Acoustic Mapping. IEEE Trans Ultrason Ferroelectr Freq Control 2018; 65:258-268. [PMID: 29389657 DOI: 10.1109/tuffc.2017.2778509] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Over the last decade, a variety of noninvasive techniques have been developed to monitor therapeutic ultrasound procedures in support of safety or efficacy assessments. One class of methods employs diagnostic ultrasound arrays to sense acoustic emissions, thereby providing a means to passively detect, localize, and quantify the strength of nonlinear sources, including cavitation. Real array element diffraction patterns may differ substantially from those presumed in existing beamforming algorithms. However, diffraction compensation has received limited treatment in passive and active imaging, and measured diffraction data have yet to be used for array response correction. The objectives of this paper were to identify differences between ideal and real element diffraction patterns, and to quantify the impact of diffraction correction on cavitation mapping beamformer performance. These objectives were addressed by performing calibration measurements on a diagnostic linear array, using the results to calculate diffraction correction terms, and applying the corrections to cavitation emission data collected from soft tissue phantom experiments. Measured diffraction patterns were found to differ significantly from those of ideal element forms, particularly at higher frequencies and shorter distances from the array. Diffraction compensation of array data resulted in cavitation energy estimates elevated by as much as a factor of 5, accompanied by the elimination of a substantial bias between two established beamforming algorithms. These results illustrate the importance of using measured array responses to validate analytical field models and to minimize observation biases in imaging applications where quantitative analyses are critical for assessment of therapeutic safety and efficacy.
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Sengupta A, Gray MD, Kelly SC, Holguin SY, Thadhani NN, Prausnitz MR. Energy Transfer Mechanisms during Molecular Delivery to Cells by Laser-Activated Carbon Nanoparticles. Biophys J 2017; 112:1258-1269. [PMID: 28355552 DOI: 10.1016/j.bpj.2017.02.007] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2016] [Revised: 02/06/2017] [Accepted: 02/07/2017] [Indexed: 11/26/2022] Open
Abstract
Previous studies have shown that exposure of carbon black nanoparticles to nanosecond pulsed near-infrared laser causes intracellular delivery of molecules through hypothesized transient breaks in the cell membrane. The goal of this study is to determine the underlying mechanisms of sequential energy transfer from laser light to nanoparticle to fluid medium to cell. We found that laser pulses on a timescale of 10 ns rapidly heat carbon nanoparticles to temperatures on the order of 1200 K. Heat is transferred from the nanoparticles to the surrounding aqueous medium on a similar timescale, causing vaporization of the surrounding water and generation of acoustic emissions. Nearby cells can be impacted thermally by the hot bubbles and mechanically by fluid mechanical forces to transiently increase cell membrane permeability. The experimental and theoretical results indicate that transfer of momentum and/or heat from the bubbles to the cells are the dominant mechanisms of energy transfer that results in intracellular uptake of molecules. We further conclude that neither thermal expansion of the nanoparticles nor a carbon-steam chemical reaction play a significant role in the observed effects on cells, and that acoustic pressure appears to be concurrent with, but not essential to, the observed bioeffects.
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Affiliation(s)
- Aritra Sengupta
- School of Chemical and Biomolecular Engineering, Georgia Institute of Technology, Atlanta, Georgia
| | - Michael D Gray
- George W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, Georgia
| | - Sean C Kelly
- School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, Georgia
| | - Stefany Y Holguin
- School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, Georgia
| | - Naresh N Thadhani
- School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, Georgia
| | - Mark R Prausnitz
- School of Chemical and Biomolecular Engineering, Georgia Institute of Technology, Atlanta, Georgia.
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Gray MD, Rogers PH. In vivo ultrasonic attenuation in cetacean soft tissues. J Acoust Soc Am 2017; 141:EL83. [PMID: 28253670 DOI: 10.1121/1.4976040] [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] [Received: 10/22/2016] [Revised: 01/12/2017] [Accepted: 01/12/2017] [Indexed: 06/06/2023]
Abstract
In vivo ultrasonic attenuation was estimated for extracranial soft tissues of two Tursiops truncatus and one Delphinapterus leucas. Backscatter data was non-invasively collected as part of routine health-based ultrasound examinations using a transducer operating in the 1.6-3.7 MHz frequency range. Data collected over the proximal mandible and temporal regions was processed to yield attenuation estimates using a reference tissue phantom whose properties had been independently determined. The estimated attenuations were at the low end of the range of literature-reported values for mammalian fatty and connective tissues. A companion model-based analysis quantified errors arising from tissue composition and sound speed uncertainties.
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Affiliation(s)
- Michael D Gray
- Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332-0405, USA ,
| | - Peter H Rogers
- Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332-0405, USA ,
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Gray MD, Rogers PH, Popper AN, Hawkins AD, Fay RR. “Large” Tank Acoustics: How Big Is Big Enough? The Effects of Noise on Aquatic Life II 2016; 875:363-9. [DOI: 10.1007/978-1-4939-2981-8_43] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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Gray MD, Lacher DW, Leonard SR, Abbott J, Zhao S, Lampel KA, Prothery E, Gouali M, Weill FX, Maurelli AT. Prevalence of Shiga toxin-producing Shigella species isolated from French travellers returning from the Caribbean: an emerging pathogen with international implications. Clin Microbiol Infect 2015; 21:765.e9-765.e14. [PMID: 25980352 DOI: 10.1016/j.cmi.2015.05.006] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [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: 02/03/2015] [Revised: 05/01/2015] [Accepted: 05/02/2015] [Indexed: 11/28/2022]
Abstract
Shiga toxins (Stxs) are potent cytotoxins that inhibit host cell protein synthesis, leading to cell death. Classically, these toxins are associated with intestinal infections due to Stx-producing Escherichia coli or Shigella dysenteriae serotype 1, and infections with these strains can lead to haemolytic-uraemic syndrome. Over the past decade, there has been increasing recognition that Stx is produced by additional Shigella species. We recently reported the presence and expression of stx genes in Shigella flexneri 2a clinical isolates. The toxin genes were carried by a new stx-encoding bacteriophage, and infection with these strains correlated with recent travel to Haiti or the Dominican Republic. In this study, we further explored the epidemiological link to this region by utilizing the French National Reference Centre for Escherichia coli, Shigella and Salmonella collection to survey the frequency of Stx-producing Shigella species isolated from French travellers returning from the Caribbean. Approximately 21% of the isolates tested were found to encode and produce Stx. These isolates included strains of S. flexneri 2a, S. flexneri Y, and S. dysenteriae 4. All of the travellers who were infected with Stx-producing Shigella had recently travelled to Haiti, the Dominican Republic, or French Guiana. Furthermore, whole genome sequencing showed that the toxin genes were encoded by a prophage that was highly identical to the phage that we identified in our previous study. These findings demonstrate that this new stx-encoding prophage is circulating within that geographical area, has spread to other continents, and is capable of spreading to multiple Shigella serogroups.
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Affiliation(s)
- M D Gray
- Uniformed Services University of the Health Sciences, Bethesda, MD, USA
| | - D W Lacher
- US Food and Drug Administration, Laurel, MD, USA
| | - S R Leonard
- US Food and Drug Administration, Laurel, MD, USA
| | - J Abbott
- US Food and Drug Administration, Laurel, MD, USA
| | - S Zhao
- US Food and Drug Administration, Laurel, MD, USA
| | - K A Lampel
- US Food and Drug Administration, Laurel, MD, USA
| | - E Prothery
- Institut Pasteur, Unité des Bactéries Pathogènes Entériques, Centre National de Référence des Escherichia coli, Shigella et Salmonella, Paris, France
| | - M Gouali
- Institut Pasteur, Unité des Bactéries Pathogènes Entériques, Centre National de Référence des Escherichia coli, Shigella et Salmonella, Paris, France
| | - F-X Weill
- Institut Pasteur, Unité des Bactéries Pathogènes Entériques, Centre National de Référence des Escherichia coli, Shigella et Salmonella, Paris, France
| | - A T Maurelli
- Uniformed Services University of the Health Sciences, Bethesda, MD, USA.
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Dale JJ, Gray MD, Popper AN, Rogers PH, Block BA. Hearing thresholds of swimming Pacific bluefin tuna Thunnus orientalis. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2015; 201:441-54. [DOI: 10.1007/s00359-015-0991-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2014] [Revised: 02/17/2015] [Accepted: 02/18/2015] [Indexed: 10/23/2022]
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Coffin AB, Zeddies DG, Fay RR, Brown AD, Alderks PW, Bhandiwad AA, Mohr RA, Gray MD, Rogers PH, Sisneros JA. Use of the swim bladder and lateral line in near-field sound source localization by fish. ACTA ACUST UNITED AC 2014; 217:2078-88. [PMID: 24675557 DOI: 10.1242/jeb.093831] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
We investigated the roles of the swim bladder and the lateral line system in sound localization behavior by the plainfin midshipman fish (Porichthys notatus). Reproductive female midshipman underwent either surgical deflation of the swim bladder or cryoablation of the lateral line and were then tested in a monopolar sound source localization task. Fish with nominally 'deflated' swim bladders performed similar to sham-deflated controls; however, post-experiment evaluation of swim bladder deflation revealed that a majority of 'deflated' fish (88%, seven of the eight fish) that exhibited positive phonotaxis had partially inflated swim bladders. In total, 95% (21/22) of fish that localized the source had at least partially inflated swim bladders, indicating that pressure reception is likely required for sound source localization. In lateral line experiments, no difference was observed in the proportion of females exhibiting positive phonotaxis with ablated (37%) versus sham-ablated (47%) lateral line systems. These data suggest that the lateral line system is likely not required for sound source localization, although this system may be important for fine-tuning the approach to the sound source. We found that midshipman can solve the 180 deg ambiguity of source direction in the shallow water of our test tank, which is similar to their nesting environment. We also found that the potential directional cues (phase relationship between pressure and particle motion) in shallow water differs from a theoretical free-field. Therefore, the general question of how fish use acoustic pressure cues to solve the 180 deg ambiguity of source direction from the particle motion vector remains unresolved.
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Affiliation(s)
- Allison B Coffin
- Virginia Merrill Bloedel Hearing Research Center, University of Washington, Seattle, WA 98195, USA Department of Otolaryngology - Head and Neck Surgery, University of Washington, Seattle, WA 98105, USA
| | | | - Richard R Fay
- Marine Biological Laboratory, Woods Hole, MA 02543, USA
| | - Andrew D Brown
- Department of Speech and Hearing Sciences, University of Washington, Seattle, WA 98105, USA
| | - Peter W Alderks
- Department of Psychology, University of Washington, Seattle, WA 98195, USA
| | - Ashwin A Bhandiwad
- Department of Psychology, University of Washington, Seattle, WA 98195, USA
| | - Robert A Mohr
- Department of Psychology, University of Washington, Seattle, WA 98195, USA
| | - Michael D Gray
- George W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - Peter H Rogers
- George W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - Joseph A Sisneros
- Virginia Merrill Bloedel Hearing Research Center, University of Washington, Seattle, WA 98195, USA Department of Psychology, University of Washington, Seattle, WA 98195, USA Department of Biology, University of Washington, Seattle, WA 98195, USA
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Fox BI, Hollingsworth JC, Gray MD, Hollingsworth ML, Gao J, Hansen RA. Developing an expert panel process to refine health outcome definitions in observational data. J Biomed Inform 2013; 46:795-804. [PMID: 23770041 DOI: 10.1016/j.jbi.2013.05.006] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2012] [Revised: 04/30/2013] [Accepted: 05/14/2013] [Indexed: 02/05/2023]
Abstract
OBJECTIVES Drug safety surveillance using observational data requires valid adverse event, or health outcome of interest (HOI) measurement. The objectives of this study were to develop a method to review HOI definitions in claims databases using (1) web-based digital tools to present de-identified patient data, (2) a systematic expert panel review process, and (3) a data collection process enabling analysis of concepts-of-interest that influence panelists' determination of HOI. METHODS De-identified patient data were presented via an interactive web-based dashboard to enable case review and determine if specific HOIs were present or absent. Criteria for determining HOIs and their severity were provided to each panelist. Using a modified Delphi method, six panelist pairs independently reviewed approximately 200 cases across each of three HOIs (acute liver injury, acute kidney injury, and acute myocardial infarction) such that panelist pairs independently reviewed the same cases. Panelists completed an assessment within the dashboard for each case that included their assessment of the presence or absence of the HOI, HOI severity (if present), and data contributing to their decision. Discrepancies within panelist pairs were resolved during a consensus process. RESULTS Dashboard development was iterative, focusing on data presentation and recording panelists' assessments. Panelists reported quickly learning how to use the dashboard. The assessment module was used consistently. The dashboard was reliable, enabling an efficient review process for panelists. Modifications were made to the dashboard and review process when necessary to facilitate case review. Our methods should be applied to other health outcomes of interest to further refine the dashboard and case review process. CONCLUSION The expert review process was effective and was supported by the web-based dashboard. Our methods for case review and classification can be applied to future methods for case identification in observational data sources.
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Affiliation(s)
- Brent I Fox
- Auburn University, Harrison School of Pharmacy, Department of Pharmacy Care Systems, 020 Foy Hall, Auburn, AL 36849, USA.
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Hansen RA, Gray MD, Fox BI, Hollingsworth JC, Gao J, Hollingsworth ML, Carpenter DM. Expert panel assessment of acute liver injury identification in observational data. Res Social Adm Pharm 2013; 10:156-67. [PMID: 23746420 DOI: 10.1016/j.sapharm.2013.04.012] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2013] [Revised: 04/18/2013] [Accepted: 04/19/2013] [Indexed: 01/16/2023]
Abstract
BACKGROUND Observational data are useful for studying drug safety; however, to be effective, accurate outcome measurement is paramount. OBJECTIVES This study compared alternative outcome definitions for acute liver injury (ALI) and explored opportunities for improving ALI identification in observational data. METHODS The Truven MarketScan® Lab Database (MSLR) was used to identify patients meeting at least 1 of 4 ALI definitions, including definitions based on diagnosis codes, laboratory measures, or combinations of diagnoses, procedures, and/or laboratory measures. Expert panelists reviewed patient data using a Web dashboard. Panelists determined whether they believed the patient had ALI and identified factors influencing their decision. Logistic regression models explored which factors were influential in case determination. RESULTS Overall, only 37 of 208 reviewed patients (17.8%) were classified as cases. The diagnosis-based definition yielded no positive cases and the laboratory-based definition yielded the most positive cases (31 of 60). The most influential factors in case classification were occurrence of procedures after the index date (OR = 13.2, 95% CI = 5.3-32.9), no occurrence of drug treatments before the index date (OR = 4.6; 95% CI = 1.6-13.2), occurrence of drug treatments before the index date (OR = 0.3; 95% CI = 0.1-0.6), and no drug treatments after the index date (OR = 0.2; 95% CI = 0.0-0.5). CONCLUSIONS Comparing ALI definitions illustrated tradeoffs between the number of plausible cases identified and the likelihood of cases being classified as positive. Future research should refine ALI case definitions, considering the import of laboratory results, procedures, and drugs in defining a case.
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Affiliation(s)
- Richard A Hansen
- Department of Pharmacy Care Systems, Harrison School of Pharmacy, Auburn University, Auburn, AL.
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Martin JS, Rogers PH, Gray MD. Pulse compression in a time variant system with application to ultrasonic vibrometry. J Acoust Soc Am 2013; 133:1503-1514. [PMID: 23464021 DOI: 10.1121/1.4789002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Pulse compression is normally applied only to time-invariant systems, as the variation of a system's properties during its interrogation violates assumptions of the compression process. However, there is an exact solution to the pulse-compression problem when the time variance satisfies two criteria, which are the same as those required for the operation of an ultrasonic vibrometer in the context of a tissue elastography system. One is that the variations be very small in comparison with the wavelength of the interrogating ultrasound. The other is that the bandwidth of the variations be within one Nyquist band as sampled by the periodic interrogation signal. The solution to this problem involves a step-wise interpolation of the static pulse-compression transfer function in the frequency domain. This technique, in conjunction with the selection of an appropriate interrogation signal, offers significant advantages in measurement time or measurement resolution for an ultrasonic vibrometer limited by additive noise at the receiver. The characteristics of optimal interrogation signals for this technique are the signal's crest factor, spectral energy distribution, and phasing. These relate to the intended compression pulse, the noise, and the static response of the system. The technique has been demonstrated analytically, experimentally, and with numerical models.
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Affiliation(s)
- J S Martin
- School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332-0405, USA.
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Zeddies DG, Fay RR, Gray MD, Alderks PW, Acob A, Sisneros JA. Local acoustic particle motion guides sound-source localization behavior in the plainfin midshipman fish, Porichthys notatus. J Exp Biol 2012; 215:152-60. [DOI: 10.1242/jeb.064998] [Citation(s) in RCA: 66] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
SUMMARY
Sound-source localization behavior was studied in the plainfin midshipman fish (Porichthys notatus) by making use of the naturally occurring phonotaxis response of gravid females to playback of the male's advertisement call. The observations took place outdoors in a circular concrete tank. A dipole sound projector was placed at the center of the tank and an 80–90 Hz tone (the approximate fundamental frequency to the male's advertisement call) was broadcast to gravid females that were released from alternative sites approximately 100 cm from the source. The phonotaxic responses of females to the source were recorded, analyzed and compared with the sound field. One release site was approximately along the vibratory axis of the dipole source, and the other was approximately orthogonal to the vibratory axis. The sound field in the tank was fully characterized through measurements of the sound pressure field using hydrophones and acoustic particle motion using an accelerometer. These measurements confirmed that the sound field was a nearly ideal dipole. When released along the dipole vibratory axis, the responding female fish took essentially straight paths to the source. However, when released approximately 90 deg to the source's vibratory axis, the responding females took highly curved paths to the source that were approximately in line with the local particle motion axes. These results indicate that the acoustic cues used by fish during sound-source localization include the axes of particle motion of the local sound field.
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Affiliation(s)
| | | | - Michael D. Gray
- George W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - Peter W. Alderks
- Department of Psychology, University of Washington, Seattle, WA 98195, USA
| | - Andrew Acob
- Department of Biology, University of Washington, Seattle, WA 98195, USA
| | - Joseph A. Sisneros
- Department of Psychology, University of Washington, Seattle, WA 98195, USA
- Department of Biology, University of Washington, Seattle, WA 98195, USA
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Abstract
A technique has been developed to demodulate periodic broadband ultrasonic interrogation signals that are returned from multiple scattering sites to simultaneously determine the low-frequency displacement time histories of each individual site. The technique employs a broadband periodic transmit signal. The motions of scattering sites are separately determined from the echoed receive signal by an algorithm involving comb filtering and pulse synthesis. This algorithm permits spatial resolution comparable to pulse-echo techniques and displacement sensitivities comparable to pure-tone techniques. A system based on this technique was used to image transient audio-frequency displacements on the order of 1-10 μm peak (≥ 50 nm/√Hz) that were produced by propagating shear waves in a tissue phantom. The system used concentric transmitting and receiving transducers and a carrier signal centered at 2.5 MHz with an 800 kHz bandwidth. The system was self-noise-limited and capable of detecting motions of strongly reflecting regions on the order of 1 nm/√Hz. System performance is limited by several factors including signal selection, component hardware, and ultrasonic propagation within the media of interest.
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Affiliation(s)
- J S Martin
- School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332-0405, USA.
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Affiliation(s)
- G M Martin
- University of Washington, Seattle 98195, USA
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Orren DK, Brosh RM, Nehlin JO, Machwe A, Gray MD, Bohr VA. Enzymatic and DNA binding properties of purified WRN protein: high affinity binding to single-stranded DNA but not to DNA damage induced by 4NQO. Nucleic Acids Res 1999; 27:3557-66. [PMID: 10446247 PMCID: PMC148601 DOI: 10.1093/nar/27.17.3557] [Citation(s) in RCA: 102] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Mutations in the WRN gene result in Werner syndrome, an autosomal recessive disease in which many characteristics of aging are accelerated. A probable role in some aspect of DNA metabolism is suggested by the primary sequence of the WRN gene product. A recombinant His-tagged WRN protein (WRNp) was overproduced in insect cells using the baculovirus system and purified to near homogeneity by several chromatographic steps. This purification scheme removes both nuclease and topoisomerase contaminants that persist following a single Ni(2+)affinity chromatography step and allows for unambiguous interpretation of WRNp enzymatic activities on DNA substrates. Purified WRNp has DNA-dependent ATPase and helicase activities consistent with its homology to the RecQ subfamily of proteins. The protein also binds with higher affinity to single-stranded DNA than to double-stranded DNA. However, WRNp has no higher affinity for various types of DNA damage, including adducts formed during 4NQO treatment, than for undamaged DNA. Our results confirm that WRNp has a role in DNA metabolism, although this role does not appear to be the specific recognition of damage in DNA.
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Affiliation(s)
- D K Orren
- Laboratory of Molecular Genetics, National Institute on Aging, National Institutes of Health, Baltimore, MD 21224, USA
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Balajee AS, Machwe A, May A, Gray MD, Oshima J, Martin GM, Nehlin JO, Brosh R, Orren DK, Bohr VA. The Werner syndrome protein is involved in RNA polymerase II transcription. Mol Biol Cell 1999; 10:2655-68. [PMID: 10436020 PMCID: PMC25497 DOI: 10.1091/mbc.10.8.2655] [Citation(s) in RCA: 111] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Werner syndrome (WS) is a human progeroid syndrome characterized by the early onset of a large number of clinical features associated with the normal aging process. The complex molecular and cellular phenotypes of WS involve characteristic features of genomic instability and accelerated replicative senescence. The gene involved (WRN) was recently cloned, and its gene product (WRNp) was biochemically characterized as a helicase. Helicases play important roles in a variety of DNA transactions, including DNA replication, transcription, repair, and recombination. We have assessed the role of the WRN gene in transcription by analyzing the efficiency of basal transcription in WS lymphoblastoid cell lines that carry homozygous WRN mutations. Transcription was measured in permeabilized cells by [3H]UTP incorporation and in vitro by using a plasmid template containing the RNA polymerase II (RNA pol II)-dependent adenovirus major late promoter. With both of these approaches, we find that the transcription efficiency in different WS cell lines is reduced to 40-60% of the transcription in cells from normal individuals. This defect can be complemented by the addition of normal cell extracts to the chromatin of WS cells. Addition of purified wild-type WRNp but not mutated WRNp to the in vitro transcription assay markedly stimulates RNA pol II-dependent transcription carried out by nuclear extracts. A nonhelicase domain (a direct repeat of 27 amino acids) also appears to have a role in transcription enhancement, as revealed by a yeast hybrid-protein reporter assay. This is further supported by the lack of stimulation of transcription when mutant WRNp lacking this domain was added to the in vitro assay. We have thus used several approaches to show a role for WRNp in RNA pol II transcription, possibly as a transcriptional activator. A deficit in either global or regional transcription in WS cells may be a primary molecular defect responsible for the WS clinical phenotype.
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Affiliation(s)
- A S Balajee
- Laboratory of Molecular Genetics, National Institute on Aging, National Institutes of Health, Baltimore, Maryland 21224, USA
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Shen JC, Gray MD, Oshima J, Kamath-Loeb AS, Fry M, Loeb LA. Werner syndrome protein. I. DNA helicase and dna exonuclease reside on the same polypeptide. J Biol Chem 1998; 273:34139-44. [PMID: 9852073 DOI: 10.1074/jbc.273.51.34139] [Citation(s) in RCA: 202] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Werner Syndrome (WS) is a human progeroid disorder characterized by genomic instability. The gene defective in WS encodes a 3' --> 5' DNA helicase (Gray, M. D., Shen, J.-C., Kamath-Loeb, A. S., Blank, A. , Sopher, B. L., Martin, G. M., Oshima, J., and Loeb, L. A.(1997) Nat. Genet. 17, 100-103). Sequence alignment analysis identified an N-terminal motif in WRN that is homologous to several exonucleases. Using combined molecular genetic, biochemical, and immunochemical approaches, we demonstrate that WRN also exhibits an integral DNA exonuclease activity. First, whereas wild-type recombinant WRN possesses both helicase and exonuclease activities, mutant WRN lacking the nuclease domain does not display exonucleolytic activity. In contrast, WRN proteins with defective helicase activity are active in exonucleolytic digestion of DNA. Second, the exonuclease co-purifies with the 160-kDa WRN protein and its associated DNA helicase and ATPase activities through successive steps of ion exchange and affinity chromatography, suggesting that all three activities are physically associated. Lastly, anti-WRN antiserum specifically co-precipitates the WRN helicase and exonuclease activities indicating that both activities reside on the same antigenic WRN polypeptide. The association of an exonuclease with WRN distinguishes it from other RecQ homologs and raises the possibility that the distinct phenotypic characteristics of WS may be due in part to a defective exonuclease.
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Affiliation(s)
- J C Shen
- Gottstein Memorial Cancer Research Laboratory, Departments of Pathology and Biochemistry, University of Washington, Seattle, Washington 98195-7705, USA
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Hu Q, Kukull WA, Bressler SL, Gray MD, Cam JA, Larson EB, Martin GM, Deeb SS. The human FE65 gene: genomic structure and an intronic biallelic polymorphism associated with sporadic dementia of the Alzheimer type. Hum Genet 1998; 103:295-303. [PMID: 9799084 DOI: 10.1007/s004390050820] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
The FE65 protein binds to the intracellular domain of the beta-amyloid precursor protein (betaPP) and may modulate the internalization of betaPP. This gene is highly expressed in regions of the brain specifically affected in dementia of the Alzheimer type (DAT). As a prelude to further investigations of the role of FE65 in the metabolism of betaPP and in the pathogenesis of DAT, we have determined the entire genomic structure and sequence of human FE65 and have discovered several polymorphisms in this gene. Human FE65 contains 14 exons ranging in size from 6 to 735 bp. All splice sites conform to consensus sequences except for the donor site of intron 10. The 5' end of FE65 mRNA was identified by rapid amplification of the cDNA 5' end and is 31 bp longer than the previously published cDNA sequence. The 5'-flanking region of this gene is TATA-less and is very GC-rich with at least five putative Sp1 binding sites. In comparison to the genomic rat FE65 sequence, the human FE65 5'-untranslated region is 134 bp longer and has an extra exon (exon 1, 86 bp). To identify mutations/polymorphisms of the coding regions of this gene, we performed blinded analysis of 457 Caucasian case-control samples from a large epidemiological study of sporadic DAT. Screening was conducted by single-strand conformation polymorphism. Four minor variants were found within the coding region, with frequencies between 0.002 and 0.015; two of the four result in amino acid substitutions. The more informative biallelic polymorphism (a trinucleotide deletion and a single base substitution) was found within intron 13 (84 bp), which interrupts two exons encoding the betaPP binding site. The frequency of the minor allele in this intron was 0.097 in DAT cases and 0.161 in controls (chi2=7.78, P=0.0054). Having at least one copy of the minor allele was associated with a decreased risk for DAT (chi2=9.20, P<0.005, odds ratio=0.49, 95% CI 0.31-0.77). Multivariate analysis showed that this association was independent of the APOE genotype. These results suggest that either FE65 itself or a closely linked gene influences the pathogenesis of sporadic DAT. The interaction of FE65 with betaPP and the association of a FE65 polymorphism with DAT lend credence to the hypothesis that the metabolism of betaPP is central to the pathogenesis of common sporadic forms of DAT.
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Affiliation(s)
- Q Hu
- Department of Pathology, University of Washington, Seattle 98195, USA
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Abstract
Mutations at the Werner helicase locus (WRN) are responsible for the Werner syndrome (WS), a "caricature of aging." We have localized the Werner protein (WRNp) to the nucleoli of replicating mammalian cells, where its appearance is associated with transcriptional activity. A dramatic reduction of the nucleolar signal and of [3H]uridine incorporation occurred when cultures were made quiescent or were exposed to 4-nitroquinoline-1-oxide (4NQO), to which WS cells are particularly susceptible. Total cellular levels of WRNp, however, did not change, and virtually all WRNp was in the nuclear fractions, consistent with translocation to the nucleoplasm and/or masking of the epitopes. The 4NQO-induced altered state of WRNp was prevented by Na3VO4, but not by okadaic acid, suggesting that WRNp localization/function is partially regulated by kinases/phosphatases for Tyr substrates on WRNp or interacting proteins. The repression of rDNA transcription by 4NQO was not reversed by Na3VO4. We suggest that physiological states and genotoxic agents modulate the interaction of WRNp with rDNA, consistent with a role of WRNp in rDNA transcription.
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Affiliation(s)
- M D Gray
- Department of Pathology, University of Washington, Seattle, Washington, 98195-4740, USA
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Shen JC, Gray MD, Oshima J, Loeb LA. Characterization of Werner syndrome protein DNA helicase activity: directionality, substrate dependence and stimulation by replication protein A. Nucleic Acids Res 1998; 26:2879-85. [PMID: 9611231 PMCID: PMC147646 DOI: 10.1093/nar/26.12.2879] [Citation(s) in RCA: 169] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Werner syndrome is an inherited disease characterized by premature aging, genetic instability and a high incidence of cancer. The wild type Werner syndrome protein (WRN) has been demonstrated to exhibit DNA helicase activity in vitro. Here we report further biochemical characterization of the WRN helicase. The enzyme unwinds double-stranded DNA, translocating 3'-->5' on the enzyme-bound strand. Hydrolysis of dATP or ATP, and to a lesser extent hydrolysis of dCTP or CTP, supports WRN-catalyzed strand-displacement. K m values for ATP and dATP are 51 and 119 microM, respectively, and 2.1 and 3.9 mM for CTP and dCTP, respectively. Strand-displacement activity of WRN is stimulated by single-stranded DNA-binding proteins (SSBs). Among the SSBs from Escherichia coli, bacteriophage T4 and human, stimulation by human SSB (human replication protein A, hRPA) is the most extensive and occurs with a stoichiometry which suggests direct interaction with WRN. A deficit in the interaction of WRN with hRPA may be associated with deletion mutations that occur at elevated frequency in Werner syndrome cells.
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Affiliation(s)
- J C Shen
- Department of Pathology, University of Washington, Box 357705, Seattle, WA 98195-7705, USA
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Ryder RE, Close CF, Krentz AJ, Gray MD, Souten H, Taylor KG, Gibson JM, Kritzinger EE. A 'fail-safe' screening programme for diabetic retinopathy. J R Coll Physicians Lond 1998; 32:134-7. [PMID: 9597629 PMCID: PMC9663005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
OBJECTIVE To improve screening for diabetic retinopathy in a hospital diabetic clinic through the use of the audit process. DESIGN Comparison of an existing system of screening for diabetic retinopathy (a specialist optometrist using ophthalmoscopy alone) with a new system in which a specialist optometrist examined retinal Polaroid photographs taken through pharmacologically dilated pupils and combined this with ophthalmoscopy in all cases except when the photographs were perfect and definitely showed no retinopathy. In this new system, the optometrist could discuss cases of uncertainty with a diabetes physician while the patient was still in the clinic with eyes dilated. SETTING Inner city hospital diabetes clinic. SUBJECTS 289 hospital diabetic clinic patients not already attending an ophthalmologist; a consecutive series of 144 such patients for the first audit, 145 for the repeat audit. MAIN OUTCOME MEASURES Assessment of each screening system against a gold standard. For the first audit this was agreement by two of four diabetes physicians, who combined examination of the photographs with the findings from dilated ophthalmoscopy, on the classification of the retinae of each patient, guided by standard European criteria. For the second audit, the gold standard was enhanced by discussing the photographs and findings of all patients with an independent ophthalmologist. For patients requiring referral, a second ophthalmologist also commented on the case. RESULTS The addition of retinal photography to universal pupil dilatation, and the availability of diabetes physician backup to discuss cases of uncertainty, greatly increased the optometrists' detection rate. Sensitivities for the first (ophthalmoscopy only) and second (ophthalmoscopy plus photography plus diabetologist back-up) audits were, respectively, 71.4% vs 100% for sight-threatening retinopathy, 33% vs 100% for retinopathy requiring six-month review, and 40.3% vs 97.2% for any retinopathy (p = 0.002). CONCLUSIONS Optometrists specialising in diabetic retinopathy using Polaroid retinal photography and ophthalmoscopy, both through dilated pupils, backed up by experienced diabetologists to discuss cases of uncertainty, could form the basis of a retinopathy screening service that accurately identifies and categorises retinopathy and does not miss sight-threatening cases.
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Affiliation(s)
- R E Ryder
- Diabetes Unit, City Hospital NHS Trust, Birmingham
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Abstract
Werner syndrome (WS) is an uncommon autosomal recessive disorder characterized by premature aging. The clinical manifestations of WS, including atherosclerosis and osteoporosis, appear early in adulthood, and death in the fourth to sixth decade commonly ensues from myocardial infarction or cancer. In accord with the aging phenotype, cells from WS patients have a reduced replicative life span in culture. Genomic instability is observed at the cytogenetic level in the form of chromosome breaks and translocations and at the molecular level by multiple large deletions. The Werner syndrome gene (WRN) has recently been cloned. The predicted product is a 1,432-amino-acid protein whose central domain is homologous to members of the RecQ family of DNA helicases. Such homology does not necessarily mean that WRN encodes an active helicase. For example, the Saccharomyces cerevisiae RAD26 gene protein and the human transcription-repair coupling factor CSB (Cockayne syndrome 8) are highly homologous to known helicases, yet neither encodes an active helicase. Moreover, the Bloom's syndrome gene (BLM), discovered before WRN, is also homologous to the RecQ family of DNA helicases, though we still await demonstration that it encodes an active helicase. Here we report that the WS protein does indeed catalyze DNA unwinding.
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Affiliation(s)
- M D Gray
- Department of Pathology, University of Washington, Seattle 98195-7705, USA
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Bressler SL, Gray MD, Sopher BL, Hu Q, Hearn MG, Pham DG, Dinulos MB, Fukuchi K, Sisodia SS, Miller MA, Disteche CM, Martin GM. cDNA cloning and chromosome mapping of the human Fe65 gene: interaction of the conserved cytoplasmic domains of the human beta-amyloid precursor protein and its homologues with the mouse Fe65 protein. Hum Mol Genet 1996; 5:1589-98. [PMID: 8894693 DOI: 10.1093/hmg/5.10.1589] [Citation(s) in RCA: 97] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Using the yeast two hybrid system, a mouse embryo cDNA library was screened for proteins that interact with the C-terminus of the human beta-amyloid precursor protein (beta PP). A fusion protein was identified that interacts specifically with the cytoplasmic domain of beta PP and does not interact with the beta-amyloid region. The protein encoded by this partial mouse cDNA is identical to the C-terminus of the rat Fe65 protein. This mouse protein also interacts with the homologous C-terminal domains of the mouse amyloid precursor-like proteins, APLP1 and APLP2. These conserved cytoplasmic regions contain a common amino acid motif, Asn-Pro-Thr-Tyr, which has previously been shown to influence both the secretion and internalization of beta PP. Fe65 has been implicated in regulatory and cell signaling mechanisms because it contains two different motifs involved in protein binding, a WW domain (a variant of Src homology 3 domains) and a phosphotyrosine interaction domain (PID). Interestingly, the PID domain binds to the same motif present in the conserved cytoplasmic domains of the beta PP and beta PP-like proteins. RNA analyses reveal that Fe65 is predominantly expressed in brain and in the regions most affected by Alzheimer's disease (AD)-associated neuropathology. The human Fe65 mRNA was cloned from a fetal brain cDNA library. The message encodes a protein of 735 amino acids that is 95% identical to the rat Fe65 protein. The human Fe65 gene was mapped on human metaphase chromosomes to band 11p15 using fluorescence in situ hybridization.
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Affiliation(s)
- S L Bressler
- Department of Pathology, University of Washington School of Medicine, Seattle 98195-7470, USA
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von Dadelszen P, Gillmer MD, Gray MD, McEwan HP, Pyper RJ, Rollason TP, Wright A. Endometrial hyperplasia and adenocarcinoma during tibolone (Livial) therapy. Br J Obstet Gynaecol 1994; 101:158-61. [PMID: 8305393 DOI: 10.1111/j.1471-0528.1994.tb13085.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Affiliation(s)
- P von Dadelszen
- Department of Obstetrics and Gynaecology, John Radcliffe Hospital, Oxford, UK
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Abstract
IMR-90 human diploid fibroblasts (HDF) lose from 30-50% of their genomic 5-methyldeoxycytidine (5mdC) during the cellular aging process. In contrast, immortal SV40-transformed IMR-90 maintain a constant level of 5mdC in culture. Precrisis SV40-transformed HDF (AG3204) represent a stage in between normal cell aging and immortalization because these cells still have a finite proliferative lifespan, but it is longer than that of normal HDF and ends in cell death rather than in G1-arrest. We find that AG3204 cells continue to lose from 12-33% of their 5mdC after a population has become 99% positive for SV40 T-antigen. Both IMR-90 cells and AG3204 cells have similar levels of 5mdC (average of 2.25%) at the end of lifespan. We investigated whether this level of 5mdC is an absolute block to further proliferation by treating IMR-90 and AG3204 cells with 5-azacytidine (5azaC) to reduce their 5mdC levels below the terminal level normally achieved at end of lifespan. We find that both IMR-90 and AG3204 cells undergo extensive proliferation with subterminal levels of 5mdC and that the lifespans of both cell types are shortened by 5azaC treatment. These studies indicate that random genomic DNA demethylation to a specific level of 5mdC is not a direct cause of finite proliferative lifespan. However, the correlation between accelerated DNA demethylation and accelerated aging still suggests that these two phenomena are related. Two ways to explain this relationship are: (1) DNA demethylation during aging is not random, and/or (2) both DNA demethylation and other independent aging processes cooperate to produce finite lifespan. In both cases, accelerated random DNA demethylation could accelerate aging, but not necessarily in direct relationship to the final genomic level of 5mdC achieved during the normal aging process.
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Affiliation(s)
- M D Gray
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado, Boulder 80309-0347
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Field D, Gray MD. Kinematic compression and expansion of the velocity distributions of particles in gas flows. Phys Rev A Gen Phys 1989; 40:1976-1982. [PMID: 9902355 DOI: 10.1103/physreva.40.1976] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Gray MD, Martin SW. An evaluation of screening programs for the detection of brucellosis in dairy herds. Can J Comp Med 1980; 44:52-60. [PMID: 7397599 PMCID: PMC1320034] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Data were collected from approximately 1000 dairy herds, initially blood tested for brucellosis in 1977, in each of southeastern and southwestern Ontario. These data were used to evaluate three brucellosis screening programs, the area recertification program, the market cow program and the milk test program. The milk test program was the most efficient program at detecting brucellosis, 29.5% of the herds tested were classified as infected, but lacked the ability to detect a large proportion of "infected" herds (relative sensitivity = 24%). The market cow program was more efficient than the area recertification program at finding infected herds, 3.9% of the herds tested under the market cow program were infected, but had a low relative sensitivity of 12%. The area recertification program was least efficient, 2.3% of herds tested under the area recertification program were infected, but had the highest relative sensitivity (53%). The relative efficiency (predictive value) of the programs was not affected significantly by location of the herds, season of the initial test or herd size. The relative sensitivity of the milk test program was significantly higher in eastern than western Ontario and tended to decrease as herd size increased. The market cow program tended to be more sensitive in the summer months. The relative specificity of the milk test program (0.997) was higher than that of the market cow program (0.960) and the area recertification program (0.884).
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Gray MD, Tracy RL, Lindberg CL. Effects of maternal interference on the attachment and exploratory behavior of one-year-olds. Child Dev 1979; 50:1211-4. [PMID: 535436] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Effects of maternal interference on social behavior toward mother and exploratory play were examined in a laboratory experimental paradigm. Subjects were 40 1-year-olds and their mothers. Mothers of the 20 interference-group infants were instructed periodically to physically interfere with their child's independent object play during the first half of the observation session. A postinterference free-play period immediately followed. The 20 control-group infants were permitted by mother to play freely throughout the session. Groups were matched for exposure to play materials. Despite its aversiveness, interference had no subsequent effect on infant social initiatives to mother, responsiveness to mother's social bids, or exploratory play.
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Schiefer B, Neitzke JP, Gray MD. Synovioma in a dog. Can Vet J 1973; 14:225-7. [PMID: 4356874 PMCID: PMC1696204] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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