1
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Wang W, Chopra B, Walawalkar V, Liang Z, Adams R, Deserno M, Ren X, Taylor RE. Cell-Surface Binding of DNA Nanostructures for Enhanced Intracellular and Intranuclear Delivery. ACS Appl Mater Interfaces 2024; 16:15783-15797. [PMID: 38497300 PMCID: PMC10995898 DOI: 10.1021/acsami.3c18068] [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] [Subscribe] [Scholar Register] [Received: 12/02/2023] [Revised: 02/20/2024] [Accepted: 03/04/2024] [Indexed: 03/19/2024]
Abstract
DNA nanostructures (DNs) have found increasing use in biosensing, drug delivery, and therapeutics because of their customizable assembly, size and shape control, and facile functionalization. However, their limited cellular uptake and nuclear delivery have hindered their effectiveness in these applications. Here, we demonstrate the potential of applying cell-surface binding as a general strategy to enable rapid enhancement of intracellular and intranuclear delivery of DNs. By targeting the plasma membrane via cholesterol anchors or the cell-surface glycocalyx using click chemistry, we observe a significant 2 to 8-fold increase in the cellular uptake of three distinct types of DNs that include nanospheres, nanorods, and nanotiles, within a short time frame of half an hour. Several factors are found to play a critical role in modulating the uptake of DNs, including their geometries, the valency, positioning and spacing of binding moieties. Briefly, nanospheres are universally preferable for cell surface attachment and internalization. However, edge-decorated nanotiles compensate for their geometry deficiency and outperform nanospheres in both categories. In addition, we confirm the short-term structural stability of DNs by incubating them with cell medium and cell lysate. Further, we investigate the endocytic pathway of cell-surface bound DNs and reveal that it is an interdependent process involving multiple pathways, similar to those of unmodified DNs. Finally, we demonstrate that cell-surface attached DNs exhibit a substantial enhancement in the intranuclear delivery. Our findings present an application that leverages cell-surface binding to potentially overcome the limitations of low cellular uptake, which may strengthen and expand the toolbox for effective cellular and nuclear delivery of DNA nanostructure systems.
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Affiliation(s)
- Weitao Wang
- Department
of Mechanical Engineering, Carnegie Mellon
University, Pittsburgh, Pennsylvania 15213, United States
| | - Bhavya Chopra
- Department
of Biomedical Engineering, Carnegie Mellon
University, Pittsburgh, Pennsylvania 15213, United States
| | - Vismaya Walawalkar
- Department
of Mechanical Engineering, Carnegie Mellon
University, Pittsburgh, Pennsylvania 15213, United States
| | - Zijuan Liang
- Department
of Mechanical Engineering, Carnegie Mellon
University, Pittsburgh, Pennsylvania 15213, United States
| | - Rebekah Adams
- Department
of Mechanical Engineering, Carnegie Mellon
University, Pittsburgh, Pennsylvania 15213, United States
| | - Markus Deserno
- Department
of Physics, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
| | - Xi Ren
- Department
of Mechanical Engineering, Carnegie Mellon
University, Pittsburgh, Pennsylvania 15213, United States
- Department
of Biomedical Engineering, Carnegie Mellon
University, Pittsburgh, Pennsylvania 15213, United States
| | - Rebecca E. Taylor
- Department
of Mechanical Engineering, Carnegie Mellon
University, Pittsburgh, Pennsylvania 15213, United States
- Department
of Biomedical Engineering, Carnegie Mellon
University, Pittsburgh, Pennsylvania 15213, United States
- Department
of Electrical and Computer Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
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2
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Beltrán SM, Bobo J, Habib A, Kodavali CV, Edwards L, Mamindla P, Taylor RE, LeDuc PR, Zinn PO. Author Correction: Characterization of neural mechanotransduction response in human traumatic brain injury organoid model. Sci Rep 2024; 14:2151. [PMID: 38273025 PMCID: PMC10810798 DOI: 10.1038/s41598-024-52553-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2024] Open
Affiliation(s)
- Susana M Beltrán
- Department of Mechanical Engineering, Carnegie Mellon University, Pittsburgh, 15213, PA, USA
| | - Justin Bobo
- Department of Mechanical Engineering, Carnegie Mellon University, Pittsburgh, 15213, PA, USA
| | - Ahmed Habib
- Department of Neurosurgery, University of Pittsburgh Medical Center, Pittsburgh, 15213, PA, USA
- Hillman Cancer Center, University of Pittsburgh Medical Center, Pittsburgh, 15232, PA, USA
| | - Chowdari V Kodavali
- Department of Neurosurgery, University of Pittsburgh Medical Center, Pittsburgh, 15213, PA, USA
- Hillman Cancer Center, University of Pittsburgh Medical Center, Pittsburgh, 15232, PA, USA
| | - Lincoln Edwards
- Department of Neurosurgery, University of Pittsburgh Medical Center, Pittsburgh, 15213, PA, USA
- Hillman Cancer Center, University of Pittsburgh Medical Center, Pittsburgh, 15232, PA, USA
| | - Priyadarshini Mamindla
- Department of Radiology, University of Pittsburgh Medical Center, Pittsburgh, 15232, PA, USA
| | - Rebecca E Taylor
- Department of Mechanical Engineering, Carnegie Mellon University, Pittsburgh, 15213, PA, USA
| | - Philip R LeDuc
- Department of Mechanical Engineering, Carnegie Mellon University, Pittsburgh, 15213, PA, USA.
| | - Pascal O Zinn
- Department of Neurosurgery, University of Pittsburgh Medical Center, Pittsburgh, 15213, PA, USA.
- Hillman Cancer Center, University of Pittsburgh Medical Center, Pittsburgh, 15232, PA, USA.
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3
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Benjaminson E, Imamura T, Lorenz A, Bergbreiter S, Travers M, Taylor RE. Buoyant magnetic milliswimmers reveal design rules for optimizing microswimmer performance. Nanoscale 2023; 15:14175-14188. [PMID: 37593931 DOI: 10.1039/d3nr02846a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/19/2023]
Abstract
Magnetically-actuated swimming microrobots are an emerging tool for navigating and manipulating materials in confined spaces. Recent work has demonstrated that it is possible to build such systems at the micro and nanoscales using polymer microspheres, magnetic particles and DNA nanotechnology. However, while these materials enable an unprecedented ability to build at small scales, such systems often demonstrate significant polydispersity resulting from both the material variations and the assembly process itself. This variability makes it difficult to predict, let alone optimize, the direction or magnitude of microswimmer velocity from design parameters such as link shape or aspect ratio. To isolate questions of a swimmer's design from variations in its physical dimensions, we present a novel experimental platform using two-photon polymerization to build a two-link, buoyant milliswimmer with a fully customizable shape and integrated flexible linker (the swimmer is underactuated, enabling asymmetric cyclic motion and net translation). Our approach enables us to control both swimming direction and repeatability of swimmer performance. These studies provide ground truth data revealing that neither the first order nor second order models currently capture the key features of milliswimmer performance. We therefore use our experimental platform to develop design guidelines for tuning the swimming speeds, and we identify the following three approaches for increasing speed: (1) tuning the actuation frequency for a fixed aspect ratio, (2) adjusting the aspect ratio given a desired range of operating frequencies, and (3) using the weaker value of linker stiffness from among the values that we tested, while still maintaining a robust connection between the links. We also find experimentally that spherical two-link swimmers with dissimilar link diameters achieve net velocities comparable to swimmers with cylindrical links, but that two-link spherical swimmers of equal diameter do not.
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Affiliation(s)
- Emma Benjaminson
- Department of Mechanical Engineering, Carnegie Mellon University, 5000 Forbes Avenue, Pittsburgh, USA.
| | - Taryn Imamura
- Department of Mechanical Engineering, Carnegie Mellon University, 5000 Forbes Avenue, Pittsburgh, USA.
| | - Aria Lorenz
- Department of Mechanical Engineering, Carnegie Mellon University, 5000 Forbes Avenue, Pittsburgh, USA.
| | - Sarah Bergbreiter
- Department of Mechanical Engineering, Carnegie Mellon University, 5000 Forbes Avenue, Pittsburgh, USA.
- Electrical and Computer Engineering, Carnegie Mellon University, 5000 Forbes Avenue, Pittsburgh, USA
- The Robotics Institute, Carnegie Mellon University, 5000 Forbes Avenue, Pittsburgh, USA
| | - Matthew Travers
- The Robotics Institute, Carnegie Mellon University, 5000 Forbes Avenue, Pittsburgh, USA
| | - Rebecca E Taylor
- Department of Mechanical Engineering, Carnegie Mellon University, 5000 Forbes Avenue, Pittsburgh, USA.
- Electrical and Computer Engineering, Carnegie Mellon University, 5000 Forbes Avenue, Pittsburgh, USA
- Department of Biomedical Engineering, Carnegie Mellon University, 5000 Forbes Avenue, Pittsburgh, USA
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4
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Beltrán SM, Bobo J, Habib A, Kodavali CV, Edwards L, Mamindla P, Taylor RE, LeDuc PR, Zinn PO. Characterization of neural mechanotransduction response in human traumatic brain injury organoid model. Sci Rep 2023; 13:13536. [PMID: 37598247 PMCID: PMC10439953 DOI: 10.1038/s41598-023-40431-y] [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: 03/08/2023] [Accepted: 08/10/2023] [Indexed: 08/21/2023] Open
Abstract
The ability to model physiological systems through 3D neural in-vitro systems may enable new treatments for various diseases while lowering the need for challenging animal and human testing. Creating such an environment, and even more impactful, one that mimics human brain tissue under mechanical stimulation, would be extremely useful to study a range of human-specific biological processes and conditions related to brain trauma. One approach is to use human cerebral organoids (hCOs) in-vitro models. hCOs recreate key cytoarchitectural features of the human brain, distinguishing themselves from more traditional 2D cultures and organ-on-a-chip models, as well as in-vivo animal models. Here, we propose a novel approach to emulate mild and moderate traumatic brain injury (TBI) using hCOs that undergo strain rates indicative of TBI. We subjected the hCOs to mild (2 s[Formula: see text]) and moderate (14 s[Formula: see text]) loading conditions, examined the mechanotransduction response, and investigated downstream genomic effects and regulatory pathways. The revealed pathways of note were cell death and metabolic and biosynthetic pathways implicating genes such as CARD9, ENO1, and FOXP3, respectively. Additionally, we show a steeper ascent in calcium signaling as we imposed higher loading conditions on the organoids. The elucidation of neural response to mechanical stimulation in reliable human cerebral organoid models gives insights into a better understanding of TBI in humans.
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Affiliation(s)
- Susana M Beltrán
- Department of Mechanical Engineering, Carnegie Mellon University, Pittsburgh, 15213, PA, USA
| | - Justin Bobo
- Department of Mechanical Engineering, Carnegie Mellon University, Pittsburgh, 15213, PA, USA
| | - Ahmed Habib
- Department of Neurosurgery, University of Pittsburgh Medical Center, Pittsburgh, 15213, PA, USA
- Hillman Cancer Center, University of Pittsburgh Medical Center, Pittsburgh, 15232, PA, USA
| | - Chowdari V Kodavali
- Department of Neurosurgery, University of Pittsburgh Medical Center, Pittsburgh, 15213, PA, USA
- Hillman Cancer Center, University of Pittsburgh Medical Center, Pittsburgh, 15232, PA, USA
| | - Lincoln Edwards
- Department of Neurosurgery, University of Pittsburgh Medical Center, Pittsburgh, 15213, PA, USA
- Hillman Cancer Center, University of Pittsburgh Medical Center, Pittsburgh, 15232, PA, USA
| | - Priyadarshini Mamindla
- Department of Radiology, University of Pittsburgh Medical Center, Pittsburgh, 15232, PA, USA
| | - Rebecca E Taylor
- Department of Mechanical Engineering, Carnegie Mellon University, Pittsburgh, 15213, PA, USA
| | - Philip R LeDuc
- Department of Mechanical Engineering, Carnegie Mellon University, Pittsburgh, 15213, PA, USA.
| | - Pascal O Zinn
- Department of Neurosurgery, University of Pittsburgh Medical Center, Pittsburgh, 15213, PA, USA.
- Hillman Cancer Center, University of Pittsburgh Medical Center, Pittsburgh, 15232, PA, USA.
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5
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Wang W, Hayes PR, Ren X, Taylor RE. Synthetic Cell Armor Made of DNA Origami. Nano Lett 2023; 23:7076-7085. [PMID: 37463308 PMCID: PMC10416349 DOI: 10.1021/acs.nanolett.3c01878] [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] [Subscribe] [Scholar Register] [Received: 05/22/2023] [Revised: 07/11/2023] [Indexed: 07/20/2023]
Abstract
The bioengineering applications of cells, such as cell printing and multicellular assembly, are directly limited by cell damage and death due to a harsh environment. Improved cellular robustness thus motivates investigations into cell encapsulation, which provides essential protection. Here we target the cell-surface glycocalyx and cross-link two layers of DNA nanorods on the cellular plasma membrane to form a modular and programmable nanoshell. We show that the DNA origami nanoshell modulates the biophysical properties of cell membranes by enhancing the membrane stiffness and lowering the lipid fluidity. The nanoshell also serves as armor to protect cells and improve their viability against mechanical stress from osmotic imbalance, centrifugal forces, and fluid shear stress. Moreover, it enables mediated cell-cell interactions for effective and robust multicellular assembly. Our results demonstrate the potential of the nanoshell, not only as a cellular protection strategy but also as a platform for cell and cell membrane manipulation.
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Affiliation(s)
- Weitao Wang
- Department
of Mechanical Engineering, Carnegie Mellon
University, Pittsburgh, Pennsylvania 15213, United States
| | - Peter R. Hayes
- Department
of Chemical Engineering, Carnegie Mellon
University, Pittsburgh, Pennsylvania 15213, United States
| | - Xi Ren
- Department
of Mechanical Engineering, Carnegie Mellon
University, Pittsburgh, Pennsylvania 15213, United States
- Department
of Biomedical Engineering, Carnegie Mellon
University, Pittsburgh, Pennsylvania 15213, United States
| | - Rebecca E. Taylor
- Department
of Mechanical Engineering, Carnegie Mellon
University, Pittsburgh, Pennsylvania 15213, United States
- Department
of Biomedical Engineering, Carnegie Mellon
University, Pittsburgh, Pennsylvania 15213, United States
- Department
of Electrical and Computer Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
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6
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Roka-Moiia Y, Walawalkar V, Liu Y, Italiano JE, Slepian MJ, Taylor RE. DNA Origami-Platelet Adducts: Nanoconstruct Binding without Platelet Activation. Bioconjug Chem 2022; 33:1295-1310. [PMID: 35731951 DOI: 10.1021/acs.bioconjchem.2c00197] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Objective. Platelets are small, mechanosensitive blood cells responsible for maintaining vascular integrity and activatable on demand to limit bleeding and facilitate thrombosis. While circulating in the blood, platelets are exposed to a range of mechanical and chemical stimuli, with the platelet membrane being the primary interface and transducer of outside-in signaling. Sensing and modulating these interface signals would be useful to study mechanochemical interactions; yet, to date, no methods have been defined to attach adducts for sensor fabrication to platelets without triggering platelet activation. We hypothesized that DNA origami, and methods for its attachment, could be optimized to enable nonactivating instrumentation of the platelet membrane. Approach and Results. We designed and fabricated multivalent DNA origami nanotile constructs to investigate nanotile hybridization to membrane-embedded single-stranded DNA-tetraethylene glycol cholesteryl linkers. Two hybridization protocols were developed and validated (Methods I and II) for rendering high-density binding of DNA origami nanotiles to human platelets. Using quantitative flow cytometry, we showed that DNA origami binding efficacy was significantly improved when the number of binding overhangs was increased from two to six. However, no additional binding benefit was observed when increasing the number of nanotile overhangs further to 12. Using flow cytometry and transmission electron microscopy, we verified that hybridization with DNA origami constructs did not cause alterations in the platelet morphology, activation, aggregation, or generation of platelet-derived microparticles. Conclusions. Herein, we demonstrate that platelets can be successfully instrumented with DNA origami constructs with no or minimal effect on the platelet morphology and function. Our protocol allows for efficient high-density binding of DNA origami to platelets using low quantities of the DNA material to label a large number of platelets in a timely manner. Nonactivating platelet-nanotile adducts afford a path for advancing the development of DNA origami nanoconstructs for cell-adherent mechanosensing and therapeutic agent delivery.
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Affiliation(s)
- Yana Roka-Moiia
- Department of Medicine, Sarver Heart Center, University of Arizona Health Sciences Center,University of Arizona, Tucson, Arizona 85721, United States
| | - Vismaya Walawalkar
- Department of Mechanical Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
| | - Ying Liu
- Department of Mechanical Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
| | - Joseph E Italiano
- Department of Surgery, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts 02115, United States
| | - Marvin J Slepian
- Department of Medicine, Sarver Heart Center, University of Arizona Health Sciences Center,University of Arizona, Tucson, Arizona 85721, United States.,Department of Biomedical Engineering, University of Arizona, Tucson, Arizona 85721, United States
| | - Rebecca E Taylor
- Department of Mechanical Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States.,Departments of Biomedical Engineering and Electrical and Computer Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
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7
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Beltran SM, Kodavali C, Bobo J, Taylor RE, Edwards L, LeDuc PR, Zinn PO. Mechanical stimulation of cerebral organoids toward understanding human neural response. Biophys J 2022. [DOI: 10.1016/j.bpj.2021.11.324] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022] Open
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8
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Abstract
Peptide nucleic acids (PNAs) have primarily been used to achieve therapeutic gene modulation through antisense strategies since their design in the 1990s. However, the application of PNAs as a functional nanomaterial has been more recent. We recently reported that γ-modified peptide nucleic acids (γPNAs) could be used to enable formation of complex, self-assembling nanofibers in select polar aprotic organic solvent mixtures. Here we demonstrate that distinct γPNA strands, each with a high density of γ-modifications can form complex nanostructures at constant temperatures within 30 minutes. Additionally, we demonstrate DNA-assisted isothermal growth of γPNA nanofibers, thereby overcoming a key hurdle for future scale-up of applications related to nanofiber growth and micropatterning.
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Affiliation(s)
- Sriram Kumar
- Department of Mechanical Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania, USA
| | - Isha Dhami
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania, USA
| | - Shivaji A Thadke
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania, USA
| | - Danith H Ly
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania, USA
| | - Rebecca E Taylor
- Department of Mechanical Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania, USA
- Department of Biomedical Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania, USA
- Department of Electrical and Computer Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania, USA
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9
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Abstract
At the nanoscale, pushing, pulling, and shearing forces drive biochemical processes in development and remodeling as well as in wound healing and disease progression. Research in the field of mechanobiology investigates not only how these loads affect biochemical signaling pathways but also how signaling pathways respond to local loading by triggering mechanical changes such as regional stiffening of a tissue. This feedback between mechanical and biochemical signaling is increasingly recognized as fundamental in embryonic development, tissue morphogenesis, cell signaling, and disease pathogenesis. Historically, the interdisciplinary field of mechanobiology has been driven by the development of technologies for measuring and manipulating cellular and molecular forces, with each new tool enabling vast new lines of inquiry. In this review, we discuss recent advances in the manufacturing and capabilities of molecular-scale force and strain sensors. We also demonstrate how DNA nanotechnology has been critical to the enhancement of existing techniques and to the development of unique capabilities for future mechanosensor assembly. DNA is a responsive and programmable building material for sensor fabrication. It enables the systematic interrogation of molecular biomechanics with forces at the 1- to 200-pN scale that are needed to elucidate the fundamental means by which cells and proteins transduce mechanical signals.
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Affiliation(s)
- Susana M Beltrán
- Department of Mechanical Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania
| | - Marvin J Slepian
- Department of Medicine and Sarver Heart Center, University of Arizona, Tucson; Department of Biomedical Engineering, University of Arizona, Tucson; Department of Materials Science and Engineering, University of Arizona, Tucson
| | - Rebecca E Taylor
- Department of Mechanical Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania; Department of Biomedical Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania; Department of Electrical and Computer Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania
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10
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Pathmarajah P, Gkini MA, Fox H, Muralidharan V, Taylor RE, Bewley A. Patients with nodular prurigo commonly have pre-existing psychological disease which requires treatment concomitant with cutaneous treatments. Br J Dermatol 2021; 185:1258-1259. [PMID: 34227098 DOI: 10.1111/bjd.20627] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2021] [Revised: 07/01/2021] [Accepted: 07/03/2021] [Indexed: 11/27/2022]
Abstract
Nodular Prurigo (NP) is a condition of the skin and mind, characterised as multiple localised or generalised itchy nodules that become excoriated as a result of intractable pruritis. It is also referred to as pruritis-related prurigo following a consensus by the EADV Task Force Pruritis in 20171 . In 2018, the European Prurigo Project (EPP) revised the terminology yet again to chronic prurigo (CPG) to encompass all clinical subtypes including NP2 . NP has an unclear aetiology and the diagnosis is based on three core criteria: (1) the presence of multiple localised or generalised pruritic lesions, (2) chronicity of pruritis defined as itch lasting more than 6 weeks, (3) history or clinical evidence of a prolonged behaviour of scratching1 . No therapy is approved for CPG as of yet.
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Affiliation(s)
- P Pathmarajah
- Department of Dermatology, Barts Health NHS Trust, London, UK
| | - M A Gkini
- Department of Dermatology, Barts Health NHS Trust, London, UK
| | - H Fox
- The London School of Medicine and Dentistry, Queen Mary University of London, UK
| | - V Muralidharan
- Department of Medicine, Sandwell and West Birmingham NHS Trust, UK
| | - R E Taylor
- Department of Liaison Psychiatry, Barts Health NHS Trust, London, UK
| | - A Bewley
- Department of Dermatology, Barts Health NHS Trust, London, UK
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11
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Kumar S, Dhami I, Thadke SA, Ly DH, Taylor RE. Rapid self-assembly of γPNA nanofibers at constant temperature. Biopolymers 2021; 112:e23463. [PMID: 34214178 DOI: 10.1002/bip.23463] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2021] [Revised: 06/10/2021] [Accepted: 06/14/2021] [Indexed: 11/07/2022]
Abstract
Peptide nucleic acids (PNAs) have primarily been used to achieve therapeutic gene modulation through antisense strategies since their design in the 1990s. However, the application of PNAs as a functional nanomaterial has been more recent. We recently reported that γ-modified peptide nucleic acids (γPNAs) could be used to enable formation of complex, self-assembling nanofibers in select polar aprotic organic solvent mixtures. Here we demonstrate that distinct γPNA strands, each with a high density of γ-modifications can form complex nanostructures at constant temperatures within 30 minutes. Additionally, we demonstrate DNA-assisted isothermal growth of γPNA nanofibers, thereby overcoming a key hurdle for future scale-up of applications related to nanofiber growth and micropatterning.
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Affiliation(s)
- Sriram Kumar
- Department of Mechanical Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania, USA
| | - Isha Dhami
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania, USA
| | - Shivaji A Thadke
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania, USA
| | - Danith H Ly
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania, USA
| | - Rebecca E Taylor
- Department of Mechanical Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania, USA.,Department of Biomedical Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania, USA.,Department of Electrical and Computer Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania, USA
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12
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Wijesekara P, Liu Y, Wang W, Johnston EK, Sullivan MLG, Taylor RE, Ren X. Accessing and Assessing the Cell-Surface Glycocalyx Using DNA Origami. Nano Lett 2021; 21:4765-4773. [PMID: 34030445 PMCID: PMC8193633 DOI: 10.1021/acs.nanolett.1c01236] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [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: 03/29/2021] [Revised: 04/21/2021] [Indexed: 05/30/2023]
Abstract
The cell-surface glycocalyx serves as a physiological barrier regulating cellular accessibility to macromolecules and other cells. Conventional glycocalyx characterization has largely been morphological rather than functional. Here, we demonstrated direct glycocalyx anchoring of DNA origami nanotiles and performed a comprehensive comparison with traditional origami targeting to the phospholipid bilayer (PLB) using cholesterol. While DNA nanotiles effectively accessed single-stranded DNA initiators anchored on the glycocalyx, their accessibility to the underlying PLB was only permitted by extended nanotile-to-initiator spacing or by enzymatic glycocalyx degradation using trypsin or pathogenic neuraminidase. Thus, the DNA nanotiles, being expelled by the physiologic glycocalyx, provide an effective functional measure of the glycocalyx barrier integrity and faithfully predict cell-to-cell accessibility during DNA-guided multicellular assembly. Lastly, the glycocalyx-anchoring mechanism enabled enhanced cell-surface stability and cellular uptake of nanotiles compared to PLB anchoring. This research lays the foundation for future development of DNA nanodevices to access the cell surface.
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Affiliation(s)
- Piyumi Wijesekara
- Department
of Biomedical Engineering, Carnegie Mellon
University, 5000 Forbes Avenue, Pittsburgh, Pennsylvania, United States
| | - Ying Liu
- Department
of Mechanical Engineering, Carnegie Mellon
University, 5000 Forbes Avenue, Pittsburgh, Pennsylvania, United States
| | - Weitao Wang
- Department
of Mechanical Engineering, Carnegie Mellon
University, 5000 Forbes Avenue, Pittsburgh, Pennsylvania, United States
| | - Elizabeth K. Johnston
- Department
of Biomedical Engineering, Carnegie Mellon
University, 5000 Forbes Avenue, Pittsburgh, Pennsylvania, United States
| | - Mara L. G. Sullivan
- Center
for Biologic Imaging, University of Pittsburgh, 3500 Terrace Street, Pittsburgh, Pennsylvania, United States
| | - Rebecca E. Taylor
- Department
of Biomedical Engineering, Carnegie Mellon
University, 5000 Forbes Avenue, Pittsburgh, Pennsylvania, United States
- Department
of Mechanical Engineering, Carnegie Mellon
University, 5000 Forbes Avenue, Pittsburgh, Pennsylvania, United States
- Department
of Electrical and Computer Engineering, Carnegie Mellon University, 5000 Forbes Avenue, Pittsburgh, Pennsylvania, United States
| | - Xi Ren
- Department
of Biomedical Engineering, Carnegie Mellon
University, 5000 Forbes Avenue, Pittsburgh, Pennsylvania, United States
- Department
of Mechanical Engineering, Carnegie Mellon
University, 5000 Forbes Avenue, Pittsburgh, Pennsylvania, United States
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13
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Danielsson BE, Tieu KV, Bathula K, Armiger TJ, Vellala PS, Taylor RE, Dahl KN, Conway DE. Lamin microaggregates lead to altered mechanotransmission in progerin-expressing cells. Nucleus 2021; 11:194-204. [PMID: 32816594 PMCID: PMC7529416 DOI: 10.1080/19491034.2020.1802906] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
The nuclear lamina is a meshwork of intermediate filament proteins, and lamin A is the primary mechanical protein. An altered splicing of lamin A, known as progerin, causes the disease Hutchinson-Gilford progeria syndrome. Progerin-expressing cells have altered nuclear shapes and stiffened nuclear lamina with microaggregates of progerin. Here, progerin microaggregate inclusions in the lamina are shown to lead to cellular and multicellular dysfunction. We show with Comsol simulations that stiffened inclusions causes redistribution of normally homogeneous forces, and this redistribution is dependent on the stiffness difference and relatively independent of inclusion size. We also show mechanotransmission changes associated with progerin expression in cells under confinement and cells under external forces. Endothelial cells expressing progerin do not align properly with patterning. Fibroblasts expressing progerin do not align properly to applied cyclic force. Combined, these studies show that altered nuclear lamina mechanics and microstructure impacts cytoskeletal force transmission through the cell.
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Affiliation(s)
- Brooke E Danielsson
- Department of Biomedical Engineering, Virginia Commonwealth University , Richmond, VA, USA
| | - Katie V Tieu
- Department of Biomedical Engineering, Virginia Commonwealth University , Richmond, VA, USA
| | - Kranthidhar Bathula
- Department of Biomedical Engineering, Virginia Commonwealth University , Richmond, VA, USA
| | - Travis J Armiger
- Chemical Engineering, Carnegie Mellon University , Pittsburgh, PA, USA
| | - Pragna S Vellala
- Department of Biomedical Engineering, Carnegie Mellon University , Pittsburgh, PA , USA
| | - Rebecca E Taylor
- Department of Biomedical Engineering, Carnegie Mellon University , Pittsburgh, PA , USA.,Department of Mechanical Engineering, Carnegie Mellon University , Pittsburgh, PA, USA
| | - Kris Noel Dahl
- Chemical Engineering, Carnegie Mellon University , Pittsburgh, PA, USA.,Department of Biomedical Engineering, Carnegie Mellon University , Pittsburgh, PA , USA
| | - Daniel E Conway
- Department of Biomedical Engineering, Virginia Commonwealth University , Richmond, VA, USA
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14
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Massoud SH, Alassaf J, Ahmed A, Taylor RE, Bewley A. UK psychodermatology services in 2019: service provision has improved but is still very poor nationally. Clin Exp Dermatol 2021; 46:1046-1051. [PMID: 33713350 DOI: 10.1111/ced.14641] [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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2020] [Revised: 02/19/2021] [Accepted: 03/08/2021] [Indexed: 11/30/2022]
Abstract
BACKGROUND Psychodermatology is an emerging subspeciality of dermatology. Psychodermatology clinics use a multidisciplinary approach to deal with psychological or psychiatric elements related to skin disease. Two previous studies in 2004 and 2012 highlighted the deficiency of psychodermatology services in the UK, despite the evidence that these services have high demand and are cost-effective. AIMS To reassess psychodermatology service provision in the UK and outline the developments that have been made. METHODS In conjunction with BBC Radio 5 Live, a survey questionnaire was distributed via email to the UK membership of the British Association of Dermatologists (BAD) and Psychodermatology UK. The survey consisted of 13 questions asking about the availability of psychodermatology services. RESULTS Basic percentages were used to analyse quantitative data, and content analysis was used for qualitative data. Our results showed that less than a quarter of the respondents (24%) have access to a nearby dedicated psychodermatology service. Additionally, the psychodermatology units do not have a unified configuration and clinical provision model differs nationally. Only around 5% of the clinicians have access to a clinic that provides psychology-dermatology-oncology service, and even fewer have access to a paediatric psychodermatology (4.8%). Engagement in psychodermatology research was reported by around 12% of the participants. CONCLUSIONS The psychocutaneous services in the UK have improved to some extent over the past decade; the service has become more widely available nationally, and the investment in research is promising. However, it is still insufficient and unable to fulfil patient demand, especially for vulnerable individuals such as children and dermato-oncology patients.
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Affiliation(s)
- S H Massoud
- Departments of Dermatology, Royal London Hospital, Barts Health NHS Trust, London, UK
| | - J Alassaf
- Departments of Dermatology, Royal London Hospital, Barts Health NHS Trust, London, UK
| | - A Ahmed
- Departments of Dermatology, Royal London Hospital, Barts Health NHS Trust, London, UK
| | - R E Taylor
- Psychiatry, Royal London Hospital, Barts Health NHS Trust, London, UK.,Department of Dermatology and Psychology, Queen Mary University London, London, UK
| | - A Bewley
- Departments of Dermatology, Royal London Hospital, Barts Health NHS Trust, London, UK.,Department of Dermatology and Psychology, Queen Mary University London, London, UK
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15
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Liu Y, Wijesekara P, Kumar S, Wang W, Ren X, Taylor RE. The effects of overhang placement and multivalency on cell labeling by DNA origami. Nanoscale 2021; 13:6819-6828. [PMID: 33885483 PMCID: PMC8161690 DOI: 10.1039/d0nr09212f] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Through targeted binding to the cell membrane, structural DNA nanotechnology has the potential to guide and affix biomolecules such as drugs, growth factors and nanobiosensors to the surfaces of cells. In this study, we investigated the targeted binding efficiency of three distinct DNA origami shapes to cultured endothelial cells via cholesterol anchors. Our results showed that the labeling efficiency is highly dependent on the shape of the origami as well as the number and the location of the binding overhangs. With a uniform surface spacing of binding overhangs, 3D isotropic nanospheres and 1D anisotropic nanorods labeled cells effectively, and the isotropic nanosphere labeling fit well with an independent binding model. Face-decoration and edge-decoration of the anisotropic nanotile were performed to investigate the effects of binding overhang location on cell labeling, and only the edge-decorated nanotiles were successful at labeling cells. Edge proximity studies demonstrated that the labeling efficiency can be modulated in both nanotiles and nanorods by moving the binding overhangs towards the edges and vertices, respectively. Furthermore, we demonstrated that while double-stranded DNA (dsDNA) bridge tethers can rescue the labeling efficiency of the face-decorated rectangular plate, this effect is also dependent on the proximity of bridge tethers to the edges or vertices of the nanostructures. A final comparison of all three nanoshapes revealed that the end-labeled nanorod and the nanosphere achieved the highest absolute labeling intensities, but the highest signal-to-noise ratio, calculated as the ratio of overall labeling to initiator-free background labeling, was achieved by the end-labeled nanorod, with the edge-labeled nanotile coming in second place slightly ahead of the nanosphere. The findings from this study can help us further understand the factors that affect membrane attachment using cholesterol anchors, thus providing guidelines for the rational design of future functional DNA nanostructures.
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Affiliation(s)
- Ying Liu
- Department of Mechanical Engineering, Carnegie Mellon University, 5000 Forbes Avenue, Pittsburgh, USA.
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16
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Wang W, Arias DS, Deserno M, Ren X, Taylor RE. Emerging applications at the interface of DNA nanotechnology and cellular membranes: Perspectives from biology, engineering, and physics. APL Bioeng 2020; 4:041507. [PMID: 33344875 PMCID: PMC7725538 DOI: 10.1063/5.0027022] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Accepted: 11/17/2020] [Indexed: 12/17/2022] Open
Abstract
DNA nanotechnology has proven exceptionally apt at probing and manipulating biological environments as it can create nanostructures of almost arbitrary shape that permit countless types of modifications, all while being inherently biocompatible. Emergent areas of particular interest are applications involving cellular membranes, but to fully explore the range of possibilities requires interdisciplinary knowledge of DNA nanotechnology, cell and membrane biology, and biophysics. In this review, we aim for a concise introduction to the intersection of these three fields. After briefly revisiting DNA nanotechnology, as well as the biological and mechanical properties of lipid bilayers and cellular membranes, we summarize strategies to mediate interactions between membranes and DNA nanostructures, with a focus on programmed delivery onto, into, and through lipid membranes. We also highlight emerging applications, including membrane sculpting, multicell self-assembly, spatial arrangement and organization of ligands and proteins, biomechanical sensing, synthetic DNA nanopores, biological imaging, and biomelecular sensing. Many critical but exciting challenges lie ahead, and we outline what strikes us as promising directions when translating DNA nanostructures for future in vitro and in vivo membrane applications.
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Affiliation(s)
- Weitao Wang
- Department of Mechanical Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, USA
| | - D. Sebastian Arias
- Department of Mechanical Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, USA
| | - Markus Deserno
- Department of Physics, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, USA
| | - Xi Ren
- Department of Biomedical Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, USA
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17
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Kumar S, Liu Y, Taylor RE. Self-Assembly of Gamma-Modified Peptide Nucleic Acids into Complex Nanostructures in Organic Solvent Mixtures. J Vis Exp 2020. [PMID: 32658204 DOI: 10.3791/61351] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
Current strategies in DNA and RNA nanotechnology enable the self-assembly of a variety of nucleic acid nanostructures in aqueous or substantially hydrated media. In this article, we describe detailed protocols that enable the construction of nanofiber architectures in organic solvent mixtures through the self-assembly of uniquely addressable, single-stranded, gamma-modified peptide nucleic acid (γPNA) tiles. Each single-stranded tile (SST) is a 12-base γPNA oligomer composed of two concatenated modular domains of 6 bases each. Each domain can bind to a mutually complimentary domain present on neighboring strands using programmed complementarity to form nanofibers that can grow to microns in length. The SST motif is made of 9 total oligomers to enable the formation of 3-helix nanofibers. In contrast with analogous DNA nanostructures, which form diameter-monodisperse structures, these γPNA systems form nanofibers that bundle along their widths during self-assembly in organic solvent mixtures. Self-assembly protocols described here therefore also include a conventional surfactant, Sodium Dodecyl Sulfate (SDS), to reduce bundling effects.
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Affiliation(s)
- Sriram Kumar
- Department of Mechanical Engineering, Carnegie Mellon University
| | - Ying Liu
- Department of Mechanical Engineering, Carnegie Mellon University
| | - Rebecca E Taylor
- Department of Mechanical Engineering, Carnegie Mellon University; Department of Biomedical Engineering, Carnegie Mellon University; Department of Electrical and Computer Engineering, Carnegie Mellon University;
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18
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Kumar S, Pearse A, Liu Y, Taylor RE. Modular self-assembly of gamma-modified peptide nucleic acids in organic solvent mixtures. Nat Commun 2020; 11:2960. [PMID: 32528008 PMCID: PMC7289805 DOI: 10.1038/s41467-020-16759-8] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2019] [Accepted: 05/20/2020] [Indexed: 02/03/2023] Open
Abstract
Nucleic acid-based materials enable sub-nanometer precision in self-assembly for fields including biophysics, diagnostics, therapeutics, photonics, and nanofabrication. However, structural DNA nanotechnology has been limited to substantially hydrated media. Transfer to organic solvents commonly used in polymer and peptide synthesis results in the alteration of DNA helical structure or reduced thermal stabilities. Here we demonstrate that gamma-modified peptide nucleic acids (γPNA) can be used to enable formation of complex, self-assembling nanostructures in select polar aprotic organic solvent mixtures. However, unlike the diameter-monodisperse populations of nanofibers formed using analogous DNA approaches, γPNA structures appear to form bundles of nanofibers. A tight distribution of the nanofiber diameters could, however, be achieved in the presence of the surfactant SDS during self-assembly. We further demonstrate nanostructure morphology can be tuned by means of solvent solution and by strand substitution with DNA and unmodified PNA. This work thereby introduces a science of γPNA nanotechnology.
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Affiliation(s)
- Sriram Kumar
- Department of Mechanical Engineering, Carnegie Mellon University, Pittsburgh, PA, USA
| | - Alexander Pearse
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, PA, USA
| | - Ying Liu
- Department of Mechanical Engineering, Carnegie Mellon University, Pittsburgh, PA, USA
| | - Rebecca E Taylor
- Department of Mechanical Engineering, Carnegie Mellon University, Pittsburgh, PA, USA. .,Department of Biomedical Engineering, Carnegie Mellon University, Pittsburgh, PA, USA. .,Department of Electrical and Computer Engineering, Carnegie Mellon University, Pittsburgh, PA, USA.
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19
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Sonmez UM, Coyle S, Taylor RE, LeDuc PR. Polycarbonate Heat Molding for Soft Lithography. Small 2020; 16:e2000241. [PMID: 32227442 DOI: 10.1002/smll.202000241] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/13/2020] [Revised: 02/28/2020] [Accepted: 03/02/2020] [Indexed: 06/10/2023]
Abstract
Soft lithography enables rapid microfabrication of many types of microsystems by replica molding elastomers into master molds. However, master molds can be very costly, hard to fabricate, vulnerable to damage, and have limited casting life. Here, an approach for the multiplication of master molds into monolithic thermoplastic sheets for further soft lithographic fabrication is introduced. The technique is tested with master molds fabricated through photolithography, mechanical micromilling as well as 3D printing, and the results are demonstrated. Microstructures with submicron feature sizes and high aspect ratios are successfully copied. The copying fidelity of the technique is quantitatively characterized and the microfluidic devices fabricated through this technique are functionally tested. This approach is also used to combine different master molds with up to 19 unique geometries into a single monolithic copy mold in a single step displaying the effectiveness of the copying technique over a large footprint area to scale up the microfabrication. This microfabrication technique can be performed outside the cleanroom without using any sophisticated equipment, suggesting a simple way for high-throughput rigid monolithic mold fabrication that can be used in analytical chemistry studies, biomedical research, and microelectromechanical systems.
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Affiliation(s)
- Utku M Sonmez
- Department of Mechanical Engineering, Carnegie Mellon University, Pittsburgh, PA, 15213, USA
| | - Stephen Coyle
- Department of Mechanical Engineering, Carnegie Mellon University, Pittsburgh, PA, 15213, USA
| | - Rebecca E Taylor
- Department of Mechanical Engineering, Carnegie Mellon University, Pittsburgh, PA, 15213, USA
| | - Philip R LeDuc
- Department of Mechanical Engineering, Carnegie Mellon University, Pittsburgh, PA, 15213, USA
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20
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Abstract
Cell penetrating peptides (CPPs), also known as protein transduction domains (PTDs), first identified ~25 years ago, are small, 6-30 amino acid long, synthetic, or naturally occurring peptides, able to carry variety of cargoes across the cellular membranes in an intact, functional form. Since their initial description and characterization, the field of cell penetrating peptides as vectors has exploded. The cargoes they can deliver range from other small peptides, full-length proteins, nucleic acids including RNA and DNA, liposomes, nanoparticles, and viral particles as well as radioisotopes and other fluorescent probes for imaging purposes. In this review, we will focus briefly on their history, classification system, and mechanism of transduction followed by a summary of the existing literature on use of CPPs as gene delivery vectors either in the form of modified viruses, plasmid DNA, small interfering RNA, oligonucleotides, full-length genes, DNA origami or peptide nucleic acids.
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Affiliation(s)
- Rebecca E. Taylor
- Mechanical Engineering, Biomedical Engineering and Electrical and Computer Engineering, Carnegie Mellon University, Pittsburgh, PA 15213, USA;
| | - Maliha Zahid
- Department of Developmental Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15201, USA
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21
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Liu Y, Kumar S, Taylor RE. Mix-and-match nanobiosensor design: Logical and spatial programming of biosensors using self-assembled DNA nanostructures. Wiley Interdiscip Rev Nanomed Nanobiotechnol 2018; 10:e1518. [PMID: 29633568 DOI: 10.1002/wnan.1518] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 09/29/2017] [Revised: 01/23/2018] [Accepted: 02/14/2018] [Indexed: 01/04/2023]
Abstract
The evergrowing need to understand and engineer biological and biochemical mechanisms has led to the emergence of the field of nanobiosensing. Structural DNA nanotechnology, encompassing methods such as DNA origami and single-stranded tiles, involves the base pairing-driven knitting of DNA into discrete one-, two-, and three-dimensional shapes at nanoscale. Such nanostructures enable a versatile design and fabrication of nanobiosensors. These systems benefit from DNA's programmability, inherent biocompatibility, and the ability to incorporate and organize functional materials such as proteins and metallic nanoparticles. In this review, we present a mix-and-match taxonomy and approach to designing nanobiosensors in which the choices of bioanalyte and transduction mechanism are fully independent of each other. We also highlight opportunities for greater complexity and programmability of these systems that are built using structural DNA nanotechnology. This article is categorized under: Implantable Materials and Surgical Technologies > Nanomaterials and Implants Diagnostic Tools > Biosensing Biology-Inspired Nanomaterials > Nucleic Acid-Based Structures Nanotechnology Approaches to Biology > Nanoscale Systems in Biology.
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Affiliation(s)
- Ying Liu
- Department of Mechanical Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania
| | - Sriram Kumar
- Department of Mechanical Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania
| | - Rebecca E Taylor
- Department of Mechanical Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania.,Department of Biomedical Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania
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22
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Meyers JL, Zhang J, Wang JC, Su J, Kuo SI, Kapoor M, Wetherill L, Bertelsen S, Lai D, Salvatore JE, Kamarajan C, Chorlian D, Agrawal A, Almasy L, Bauer L, Bucholz KK, Chan G, Hesselbrock V, Koganti L, Kramer J, Kuperman S, Manz N, Pandey A, Seay M, Scott D, Taylor RE, Dick DM, Edenberg HJ, Goate A, Foroud T, Porjesz B. An endophenotype approach to the genetics of alcohol dependence: a genome wide association study of fast beta EEG in families of African ancestry. Mol Psychiatry 2017; 22:1767-1775. [PMID: 28070124 PMCID: PMC5503794 DOI: 10.1038/mp.2016.239] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/17/2016] [Revised: 09/24/2016] [Accepted: 10/27/2016] [Indexed: 01/16/2023]
Abstract
Fast beta (20-28 Hz) electroencephalogram (EEG) oscillatory activity may be a useful endophenotype for studying the genetics of disorders characterized by neural hyperexcitability, including substance use disorders (SUDs). However, the genetic underpinnings of fast beta EEG have not previously been studied in a population of African-American ancestry (AA). In a sample of 2382 AA individuals from 482 families drawn from the Collaborative Study on the Genetics of Alcoholism (COGA), we performed a genome-wide association study (GWAS) on resting-state fast beta EEG power. To further characterize our genetic findings, we examined the functional and clinical/behavioral significance of GWAS variants. Ten correlated single-nucleotide polymorphisms (SNPs) (r2>0.9) located in an intergenic region on chromosome 3q26 were associated with fast beta EEG power at P<5 × 10-8. The most significantly associated SNP, rs11720469 (β: -0.124; P<4.5 × 10-9), is also an expression quantitative trait locus for BCHE (butyrylcholinesterase), expressed in thalamus tissue. Four of the genome-wide SNPs were also associated with Diagnostic and Statistical Manual of Mental Disorders Alcohol Dependence in COGA AA families, and two (rs13093097, rs7428372) were replicated in an independent AA sample (Gelernter et al.). Analyses in the AA adolescent/young adult (offspring from COGA families) subsample indicated association of rs11720469 with heavy episodic drinking (frequency of consuming 5+ drinks within 24 h). Converging findings presented in this study provide support for the role of genetic variants within 3q26 in neural and behavioral disinhibition. These novel genetic findings highlight the importance of including AA populations in genetics research on SUDs and the utility of the endophenotype approach in enhancing our understanding of mechanisms underlying addiction susceptibility.
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Affiliation(s)
- JL Meyers
- Department of Psychiatry, State University of New York Downstate Medical Center, Brooklyn, NY, USA
| | - J Zhang
- Department of Psychiatry, State University of New York Downstate Medical Center, Brooklyn, NY, USA
| | - JC Wang
- Department of Neuroscience, Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - J Su
- Department of Psychology, Virginia Commonwealth University, Richmond, VA, USA
| | - SI Kuo
- Department of Psychology, Virginia Commonwealth University, Richmond, VA, USA
| | - M Kapoor
- Department of Neuroscience, Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - L Wetherill
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, IN, USA
| | - S Bertelsen
- Department of Neuroscience, Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - D Lai
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, IN, USA
| | - JE Salvatore
- Department of Psychology, Virginia Commonwealth University, Richmond, VA, USA,Virginia Institute of Psychiatric and Behavioral Genetics, Virginia Commonwealth University, Richmond, VA, USA
| | - C Kamarajan
- Department of Psychiatry, State University of New York Downstate Medical Center, Brooklyn, NY, USA
| | - D Chorlian
- Department of Psychiatry, State University of New York Downstate Medical Center, Brooklyn, NY, USA
| | - A Agrawal
- Department of Psychiatry, Washington University School of Medicine in St Louis, St Louis, MO, USA
| | - L Almasy
- Department of Biomedical and Health Informatics, The Children’s Hospital of Philadelphia, Philadelphia, PA, USA,Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - L Bauer
- Department of Psychiatry, University of Connecticut School of Medicine, Farmington, CT, USA
| | - KK Bucholz
- Department of Psychiatry, Washington University School of Medicine in St Louis, St Louis, MO, USA
| | - G Chan
- Department of Psychiatry, University of Connecticut School of Medicine, Farmington, CT, USA
| | - V Hesselbrock
- Department of Psychiatry, University of Connecticut School of Medicine, Farmington, CT, USA
| | - L Koganti
- Department of Neuroscience, Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - J Kramer
- Department of Psychiatry, University of Iowa Carver College of Medicine, Iowa City, IA, USA
| | - S Kuperman
- Department of Psychiatry, University of Iowa Carver College of Medicine, Iowa City, IA, USA
| | - N Manz
- Department of Physics, The College of Wooster, Wooster, OH, USA
| | - A Pandey
- Department of Psychiatry, State University of New York Downstate Medical Center, Brooklyn, NY, USA
| | - M Seay
- Department of Psychiatry, State University of New York Downstate Medical Center, Brooklyn, NY, USA
| | - D Scott
- Collaborative Alcohol Research Center, Howard University College of Medicine, Washington, DC, USA
| | - RE Taylor
- Collaborative Alcohol Research Center, Howard University College of Medicine, Washington, DC, USA
| | - DM Dick
- Department of Psychology, Virginia Commonwealth University, Richmond, VA, USA,Virginia Institute of Psychiatric and Behavioral Genetics, Virginia Commonwealth University, Richmond, VA, USA
| | - HJ Edenberg
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, IN, USA,Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, IN, USA
| | - A Goate
- Department of Neuroscience, Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, USA,Department of Neurology, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - T Foroud
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, IN, USA
| | - B Porjesz
- Department of Psychiatry, State University of New York Downstate Medical Center, Brooklyn, NY, USA
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23
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Reiner WB, Masao F, Sholts SB, Songita AV, Stanistreet I, Stollhofen H, Taylor RE, Hlusko LJ. OH 83: A new early modern human fossil cranium from the Ndutu beds of Olduvai Gorge, Tanzania. Am J Phys Anthropol 2017; 164:533-545. [PMID: 28786473 DOI: 10.1002/ajpa.23292] [Citation(s) in RCA: 3] [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] [Subscribe] [Scholar Register] [Received: 05/23/2016] [Revised: 05/02/2017] [Accepted: 07/23/2017] [Indexed: 01/23/2023]
Abstract
OBJECTIVE Herein we introduce a newly recovered partial calvaria, OH 83, from the upper Ndutu Beds of Olduvai Gorge, Tanzania. We present the geological context of its discovery and a comparative analysis of its morphology, placing OH 83 within the context of our current understanding of the origins and evolution of Homo sapiens. MATERIALS AND METHODS We comparatively assessed the morphology of OH 83 using quantitative and qualitative data from penecontemporaneous fossils and the W.W. Howells modern human craniometric dataset. RESULTS OH 83 is geologically dated to ca. 60-32 ka. Its morphology is indicative of an early modern human, falling at the low end of the range of variation for post-orbital cranial breadth, the high end of the range for bifrontal breadth, and near average in frontal length. DISCUSSION There have been numerous attempts to use cranial anatomy to define the species Homo sapiens and identify it in the fossil record. These efforts have not met wide agreement by the scientific community due, in part, to the mosaic patterns of cranial variation represented by the fossils. The variable, mosaic pattern of trait expression in the crania of Middle and Late Pleistocene fossils implies that morphological modernity did not occur at once. However, OH 83 demonstrates that by ca. 60-32 ka modern humans in Africa included individuals that are at the fairly small and gracile range of modern human cranial variation.
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Affiliation(s)
- Whitney B Reiner
- Department of Integrative Biology, University of California Berkeley, MC 3140, Berkeley, California, 94720
| | - Fidelis Masao
- University of Dar es Salaam, Dar es Salaam, TZ, 35091.,Conservation Olduvai Project, Dar es Salaam, TZ, 35091
| | - Sabrina B Sholts
- Department of Anthropology, National Museum of Natural History, Smithsonian Institution, Washington, DC, 20560
| | | | - Ian Stanistreet
- University of Liverpool, Liverpool, L69 3GP, UK.,The Stone Age Institute, Bloomington, Indiana, 47407
| | - Harald Stollhofen
- GeoZentrum Nordbayern, Universität Erlangen-Nürnberg, Erlangen, 91054, Germany
| | - R E Taylor
- University of California Riverside, Riverside, California, 92521
| | - Leslea J Hlusko
- Department of Integrative Biology, University of California Berkeley, MC 3140, Berkeley, California, 94720
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24
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Anyasodor MC, Taylor RE, Bewley A, Goulding JMR. Dysaesthetic penoscrotodynia may be a somatoform disorder: results from a two-centre retrospective case series. Clin Exp Dermatol 2016; 41:474-9. [PMID: 26932754 DOI: 10.1111/ced.12824] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/25/2015] [Indexed: 11/29/2022]
Abstract
BACKGROUND Dysaesthetic penoscrotodynia (DPSD) is a poorly understood disorder, in which men experience distressing symptoms such as burning pain in their genital skin. Drugs for neuropathic pain are often used, but with little success. AIM To review a series of patients with DPSD to highlight common themes and response to treatment. METHODS Ten consecutive patients with DPSD were identified from specialist male genital dermatology and psychodermatology clinics at two centres. Clinical details, including psychiatric history, were reviewed retrospectively. Patients with no previously diagnosed psychiatric illness completed either the Generalized Anxiety Disorder (GAD)-7 scale and the Patient Health Questionnaire (PHQ)-9 depression scale, or the Hospital Anxiety and Depression Scale (HADS) and the Dermatology Life Quality Index (DLQI). RESULTS Of the 10 patients, 9 had known or newly diagnosed psychopathology. All patients were offered psychodermatological treatment, of which 7 of 10 accepted. All of those who accepted psychodermatological treatment experienced an improvement in their genital symptoms. When post-treatment scores were collected, improvement in psychiatric symptoms accompanied improvement in genital symptoms. CONCLUSIONS Psychopathology is almost invariably present in individuals with DPSD, yet these patients rarely volunteer such information. DPSD is most likely to constitute a functional somatic symptom disorder, hence psychodermatological treatment is indicated for its management. This concept reflects a significant change in the approach to this condition.
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Affiliation(s)
- M C Anyasodor
- Department of Dermatology, Barts Health NHS Trust, London, UK
| | - R E Taylor
- Barts and The London School of Medicine and Dentistry Centre for Psychiatry, London, UK
| | - A Bewley
- Department of Dermatology, Barts Health NHS Trust, London, UK
| | - J M R Goulding
- Department of Dermatology, Heart of England NHS Foundation Trust, Birmingham, UK
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25
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Whitesell PL, Owoyemi O, Oneal P, Nouraie M, Klings ES, Rock A, Mellman TA, Berihun T, Lavella J, Taylor RE, Perrine SP. Sleep-disordered breathing and nocturnal hypoxemia in young adults with sickle cell disease. Sleep Med 2016; 22:47-49. [PMID: 27544835 DOI: 10.1016/j.sleep.2016.05.006] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/16/2016] [Revised: 04/13/2016] [Accepted: 05/19/2016] [Indexed: 01/26/2023]
Abstract
Sleep-disordered breathing (SDB) is reported in up to 69% of adolescents and children with sickle cell disease (SCD) [1], but data regarding the prevalence of SDB in adults with SCD are limited. In order to obtain a preliminary assessment of the frequency and degree of sleep-related hypoxemia and potential associations with cardiovascular function in adults with SCD, we conducted overnight sleep studies, 6-min walk tests, echocardiograms, and hematologic and chemistry panels, calculated the Pittsburgh sleep quality index (PSQI), and conducted fatigue- and health-related quality-of-life measurement in 20 young adults with SCD visiting a sickle cell clinic for routine care. Sleep apnea, defined as an apnea-hypopnea index (AHI) > 5 events/h, was found in 50% of patients. Traditional clinical indicators, such as obesity, the presence of snoring, and reported sleep complaints, did not reliably differentiate them. The patients with AHI > 5 had higher mean systolic blood pressure (p = 0.03), evidence of impaired left ventricular diastolic function (i.e., increased mitral valve E/A ratio, p = 0.05), a trend toward higher reduction in 6-min walk distances (p = 0.06), and lower health-related quality-of-life scores (p ≤ 0.01). Three of nine patients with more severe anemia (total Hb < 9.0) showed nocturnal hypoxemia in the absence of sleep apnea. As prolonged and frequent hypoxemic episodes likely increase risks for vaso-occlusive, cardiovascular, and neurologic complications of SCD, these results suggest that the prevalence and severity of SDB should be investigated further in studies of larger patient populations. If confirmed, these findings could identify opportunities to prevent or reduce nocturnal hypoxia and improve outcomes.
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Affiliation(s)
- P L Whitesell
- Department of Medicine, Howard University College of Medicine, Washington D.C., USA.
| | - O Owoyemi
- Center for Hemoglobin Research in Minorities, Howard University College of Medicine, Washington D.C., USA
| | - P Oneal
- Center for Hemoglobin Research in Minorities, Howard University College of Medicine, Washington D.C., USA
| | - M Nouraie
- Department of Medicine, Howard University College of Medicine, Washington D.C., USA; Center for Hemoglobin Research in Minorities, Howard University College of Medicine, Washington D.C., USA
| | - E S Klings
- Hemoglobinopathy Thalassemia Research Unit, The Pulmonary Center, Center of Excellence in Sickle Cell Disease, Boston University School of Medicine, Boston, MA, USA
| | - A Rock
- Center for Hemoglobin Research in Minorities, Howard University College of Medicine, Washington D.C., USA
| | - T A Mellman
- Georgetown-Howard Universities Center for Clinical and Translational Science, Washington, DC, USA; Department of Psychiatry and Behavioral Sciences, Howard University College of Medicine, Washington D.C., USA
| | - T Berihun
- Georgetown-Howard Universities Center for Clinical and Translational Science, Washington, DC, USA
| | - J Lavella
- Georgetown-Howard Universities Center for Clinical and Translational Science, Washington, DC, USA
| | - R E Taylor
- Department of Medicine, Howard University College of Medicine, Washington D.C., USA; Center for Hemoglobin Research in Minorities, Howard University College of Medicine, Washington D.C., USA
| | - S P Perrine
- Center for Hemoglobin Research in Minorities, Howard University College of Medicine, Washington D.C., USA; Hemoglobinopathy Thalassemia Research Unit, The Pulmonary Center, Center of Excellence in Sickle Cell Disease, Boston University School of Medicine, Boston, MA, USA
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Taylor RE, Boyce CM, Boyce MC, Pruitt BL. Planar patterned stretchable electrode arrays based on flexible printed circuits. J Micromech Microeng 2013; 23:10.1088/0960-1317/23/10/105004. [PMID: 24244075 PMCID: PMC3826909 DOI: 10.1088/0960-1317/23/10/105004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
For stretchable electronics to achieve broad industrial application, they must be reliable to manufacture and must perform robustly while undergoing large deformations. We present a new strategy for creating planar stretchable electronics and demonstrate one such device, a stretchable microelectrode array based on flex circuit technology. Stretchability is achieved through novel, rationally designed perforations that provide islands of low strain and continuous low-strain pathways for conductive traces. This approach enables the device to maintain constant electrical properties and planarity while undergoing applied strains up to 15%. Materials selection is not limited to polyimide composite devices and can potentially be implemented with either soft or hard substrates and can incorporate standard metals or new nano-engineered conductors. By using standard flex circuit technology, our planar microelectrode device achieved constant resistances for strains up to 20% with less than a 4% resistance offset over 120,000 cycles at 10% strain.
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Affiliation(s)
- R E Taylor
- Department of Mechanical Engineering, Stanford University, CA 94305 (USA)
| | - C M Boyce
- Infinite Corridor Technology, LLC, Winchester, MA 01890 (USA)
| | - M C Boyce
- Infinite Corridor Technology, LLC, Winchester, MA 01890 (USA)
- Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139 (USA)
| | - B L Pruitt
- Department of Mechanical Engineering, Stanford University, CA 94305 (USA)
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Taylor RE, Kim K, Sun N, Park SJ, Sim JY, Fajardo G, Bernstein D, Wu JC, Pruitt BL. Sacrificial layer technique for axial force post assay of immature cardiomyocytes. Biomed Microdevices 2013; 15:171-81. [PMID: 23007494 PMCID: PMC3545035 DOI: 10.1007/s10544-012-9710-3] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Immature primary and stem cell-derived cardiomyocytes provide useful models for fundamental studies of heart development and cardiac disease, and offer potential for patient specific drug testing and differentiation protocols aimed at cardiac grafts. To assess their potential for augmenting heart function, and to gain insight into cardiac growth and disease, tissue engineers must quantify the contractile forces of these single cells. Currently, axial contractile forces of isolated adult heart cells can only be measured by two-point methods such as carbon fiber techniques, which cannot be applied to neonatal and stem cell-derived heart cells because they are more difficult to handle and lack a persistent shape. Here we present a novel axial technique for measuring the contractile forces of isolated immature cardiomyocytes. We overcome cell manipulation and patterning challenges by using a thermoresponsive sacrificial support layer in conjunction with arrays of widely separated elastomeric microposts. Our approach has the potential to be high-throughput, is functionally analogous to current gold-standard axial force assays for adult heart cells, and prescribes elongated cell shapes without protein patterning. Finally, we calibrate these force posts with piezoresistive cantilevers to dramatically reduce measurement error typical for soft polymer-based force assays. We report quantitative measurements of peak contractile forces up to 146 nN with post stiffness standard error (26 nN) far better than that based on geometry and stiffness estimates alone. The addition of sacrificial layers to future 2D and 3D cell culture platforms will enable improved cell placement and the complex suspension of cells across 3D constructs.
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Affiliation(s)
- Rebecca E Taylor
- Department of Mechanical Engineering and Stanford Cardiovascular Institute, Stanford University, Stanford, CA 94305, USA
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Woolf RT, Bewley AP, Taylor RE, D'Souza A, Hoque SR. A difficult case of dermatitis artefacta requiring surgical intervention. Br J Dermatol 2012; 168:889-91. [PMID: 23061788 DOI: 10.1111/bjd.12086] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Sitzabee WE, Taylor RE. Professional Licensure: Is It an Air Force Ethical Requirement? J Prof Issues Eng Educ Pract 2012. [DOI: 10.1061/(asce)ei.1943-5541.0000083] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
Affiliation(s)
- William E. Sitzabee
- Lieutenant Colonel, Air Force Institute of Technology, 2950 Hobson Way, Building 641, Wright-Patterson AFB, OH 45433 (corresponding author)
| | - Rebecca E. Taylor
- Ms., Research Assistant, Air Force Institute of Technology, 2950 Hobson Way, Building 641, Wright-Patterson AFB, OH 45433
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Taylor RE, Marshall T, Mann A, Goldberg DP. Insecure attachment and frequent attendance in primary care: a longitudinal cohort study of medically unexplained symptom presentations in ten UK general practices. Psychol Med 2012; 42:855-864. [PMID: 21880165 DOI: 10.1017/s0033291711001589] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
BACKGROUND In primary care frequent attenders with medically unexplained symptoms (MUS) pose a clinical and health resource challenge. We sought to understand these presentations in terms of the doctor-patient relationship, specifically to test the hypothesis that such patients have insecure emotional attachment. METHOD We undertook a cohort follow-up study of 410 patients with MUS. Baseline questionnaires assessed adult attachment style, psychological distress, beliefs about the symptom, non-specific somatic symptoms, and physical function. A telephone interview following consultation assessed health worry, general practitioner (GP) management and satisfaction with consultation. The main outcome was annual GP consultation rate. RESULTS Of consecutive attenders, 18% had an MUS. This group had a high mean consultation frequency of 5.24 [95% confidence interval (CI) 4.79-5.69] over the follow-up year. The prevalence of insecure attachment was 28 (95% CI 23-33) %. A significant association was found between insecure attachment style and frequent attendance, even after adjustment for sociodemographic characteristics, presence of chronic physical illness and baseline physical function [odds ratio (OR) 1.96 (95% CI 1.05-3.67)]. The association was particularly strong in those patients who believed that there was a physical cause for their initial MUS [OR 9.52 (95% CI 2.67-33.93)]. A possible model for the relationship between attachment style and frequent attendance is presented. CONCLUSIONS Patients with MUS who attend frequently have insecure adult attachment styles, and their high consultation rate may therefore be conceptualized as pathological care-seeking behaviour linked to their insecure attachment. Understanding frequent attendance as pathological help seeking driven by difficulties in relating to caregiving figures may help doctors to manage their frequently attending patients in a different way.
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Affiliation(s)
- R E Taylor
- Barts and the London School of Medicine and Dentistry, Queen Mary, Charterhouse Square, London, UK.
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Abstract
Delusional infestation (DI) is a psychiatric disorder characterized by a fixed, false belief that the patient is infested with extracorporeal agents. It is known by several names, including the more commonly used term 'delusional parasitosis'. The psychiatric disease is responsible for the cutaneous pathology. About 90% of patients with DI seek help from dermatologists, and most reject psychiatric referral. Thus, effective management requires incorporation of psychiatric principles. We report three cases of DI with inanimate materials, and examine 'Morgellons' disease. We believe that patients with unusual presentations of DI are likely to be seen more commonly in the future. These patients appear to be a subgroup of DI, and may be even more difficult to treat than other patients with DI.
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Affiliation(s)
- P Dewan
- Department of Dermatology, Royal London Hospital, London, UK.
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Pang H, Shiwalkar AP, Madormo CM, Taylor RE, Andriacchi TP, Kuhl E. Computational modeling of bone density profiles in response to gait: a subject-specific approach. Biomech Model Mechanobiol 2011; 11:379-90. [PMID: 21604146 DOI: 10.1007/s10237-011-0318-y] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2011] [Accepted: 05/08/2011] [Indexed: 11/29/2022]
Abstract
The goal of this study is to explore the potential of computational growth models to predict bone density profiles in the proximal tibia in response to gait-induced loading. From a modeling point of view, we design a finite element-based computational algorithm using the theory of open system thermodynamics. In this algorithm, the biological problem, the balance of mass, is solved locally on the integration point level, while the mechanical problem, the balance of linear momentum, is solved globally on the node point level. Specifically, the local bone mineral density is treated as an internal variable, which is allowed to change in response to mechanical loading. From an experimental point of view, we perform a subject-specific gait analysis to identify the relevant forces during walking using an inverse dynamics approach. These forces are directly applied as loads in the finite element simulation. To validate the model, we take a Dual-Energy X-ray Absorptiometry scan of the subject's right knee from which we create a geometric model of the proximal tibia. For qualitative validation, we compare the computationally predicted density profiles to the bone mineral density extracted from this scan. For quantitative validation, we adopt the region of interest method and determine the density values at fourteen discrete locations using standard and custom-designed image analysis tools. Qualitatively, our two- and three-dimensional density predictions are in excellent agreement with the experimental measurements. Quantitatively, errors are less than 3% for the two-dimensional analysis and less than 10% for the three-dimensional analysis. The proposed approach has the potential to ultimately improve the long-term success of possible treatment options for chronic diseases such as osteoarthritis on a patient-specific basis by accurately addressing the complex interactions between ambulatory loads and tissue changes.
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Affiliation(s)
- Henry Pang
- Department of Mechanical Engineering, Stanford University, Stanford, CA 94305, USA
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Taylor RE, Zheng C, Jackson RP, Doll JC, Chen JC, Holzbaur KRS, Besier T, Kuhl E. The phenomenon of twisted growth: humeral torsion in dominant arms of high performance tennis players. Comput Methods Biomech Biomed Engin 2009; 12:83-93. [PMID: 18654877 DOI: 10.1080/10255840903077212] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
This manuscript is driven by the need to understand the fundamental mechanisms that cause twisted bone growth and shoulder pain in high performance tennis players. Our ultimate goal is to predict bone mass density in the humerus through computational analysis. The underlying study spans a unique four level complete analysis consisting of a high-speed video analysis, a musculoskeletal analysis, a finite element based density growth analysis and an X-ray based bone mass density analysis. For high performance tennis players, critical loads are postulated to occur during the serve. From high-speed video analyses, the serve phases of maximum external shoulder rotation and ball impact are identified as most critical loading situations for the humerus. The corresponding posts from the video analysis are reproduced with a musculoskeletal analysis tool to determine muscle attachment points, muscle force vectors and overall forces of relevant muscle groups. Collective representative muscle forces of the deltoid, latissimus dorsi, pectoralis major and triceps are then applied as external loads in a fully 3D finite element analysis. A problem specific nonlinear finite element based density analysis tool is developed to predict functional adaptation over time. The density profiles in response to the identified critical muscle forces during serve are qualitatively compared to X-ray based bone mass density analyses.
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Affiliation(s)
- R E Taylor
- Department of Mechanical Engineering, Stanford University, Stanford, CA, USA
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Prestwich RJ, Picton SV, Glaser A, Taylor RE. Fatal pneumonitis in children with metastatic rhabdomyosarcoma following whole lung radiotherapy and sequential epirubicin. Pediatr Blood Cancer 2007; 48:586-90. [PMID: 16302221 DOI: 10.1002/pbc.20660] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Interstitial pneumonitis is a recognized complication following whole lung radiotherapy. We report two cases in which fatal pneumonitis appeared to be precipitated by the administration of epirubicin-containing combination chemotherapy within 7 weeks of completion of whole lung radiotherapy. These cases highlight a potentially fatal interaction between radiotherapy and modern chemotherapy regimens.
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Affiliation(s)
- R J Prestwich
- Department of Clinical Oncology, Cookridge Hospital, Yorkshire Cancer Centre, West Yorkshire, UK.
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Barto RR, Frank CW, Bedworth PV, Taylor RE, Anderson WW, Ermer S, Jen AKY, Luo JD, Ma H, Tang HZ, Lee M, Ren AS. Bonding and Molecular Environment Effects on Near-Infrared Optical Absorption Behavior in Nonlinear Optical Monoazo Chromophore−Polymer Materials. Macromolecules 2006. [DOI: 10.1021/ma060033k] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
- Richard R. Barto
- Department of Materials Science and Engineering, Stanford University, Stanford, California
| | - Curtis W. Frank
- Department of Chemical Engineering, Stanford University, Stanford, California
| | | | | | | | | | | | | | | | - Hong-Zhi Tang
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina
| | | | - Albert S. Ren
- Arena Pharmaceuticals, Inc., 6166 Nancy Ridge Drive, San Diego, California 92121
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Abstract
Orbital infiltration by acute lymphoblastic leukemia is rare. The authors present 3 patients, 2 with optic nerve involvement and 1 with anterior chamber infiltration, treated by chemotherapy and radiotherapy. Two are in continuous remission at 64 and 59 months and 1 relapsed in the central nervous system 35 months after ocular relapse. Visual deterioration was prevented in two. Early diagnosis and treatment are important for preservation of vision.
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Affiliation(s)
- C W Taylor
- Cookridge Hospital, Leeds, United Kingdom.
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Barto RR, Frank CW, Bedworth PV, Ermer S, Taylor RE. Near-infrared optical-absorption behavior in high-beta nonlinear optical chromophore-polymer guest-host materials. II. Dye spacer length effects in an amorphous polycarbonate copolymer host. J Chem Phys 2005; 122:234907. [PMID: 16008487 DOI: 10.1063/1.1929742] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
In the second of a three-part series, spectral absorption behavior of nonlinear optical (NLO) dyes incorporated into amorphous polycarbonate, comprised of a homologous series of dialkyl spacer groups extending from the midsection of the dye molecule, is characterized by UV-Vis and photothermal deflection spectroscopy. The dyes are structural analogs of the NLO dye FTC [2-(3-cyano-4-{2-[5-(2-{4-[ethyl-(2-methoxyethyl)amino]phenyl}vinyl)-3,4-diethylthiophen-2-yl]vinyl}-5,5-dimethyl-5H-furan-2-ylidene)malononitrile]. Previous Monte Carlo calculations [B. H. Robinson and L. R. Dalton, J. Phys. Chem. A 104, 4785 (2000)] predict a strong dependence of the macroscopic nonlinear optical susceptibility on the chromophore waist: length aspect ratio in electric-field-poled films arising from interactions between chromophores. It is expected that these interactions will play a role in the absorption characteristics of unpoled films, as well. The spacer groups range in length from diethyl to dihexyl, and each dye is studied over a wide range of concentrations. Among the four dyes studied, a universal dependence of near-IR loss on inhomogeneous broadening of the dye main absorption peak is found. The inhomogeneous width and its concentration dependence are seen to vary with spacer length in a manner characteristic of the near-IR loss-concentration slope at transmission wavelengths of 1.06 and 1.3 mum, but not at 1.55 mum. The lower wavelength loss behavior is assigned to purely Gaussian broadening, and is described by classical mixing thermodynamic quantities based on the Marcus theory of inhomogeneous broadening [R. A. Marcus, J. Chem. Phys. 43, 1261 (1965)], modeled as a convolution of dye-dye dipole broadening and dye-polymer van der Waals broadening. The Gaussian dipole interactions follow a Loring dipole-broadening description [R. F. Loring, J. Phys. Chem. 94, 513 (1990)] dominated by the excited-state dipole moment, and have a correlated homogeneous broadening contribution. The long-wavelength loss behavior has a non-Gaussian dye-dye dipole contribution which follows Kador's broadening analysis [L. Kador, J. Chem. Phys. 95, 5574 (1991)], with a net broadening described by a convolution of this term with a Gaussian van der Waals interaction given by Obata et al. [M. Obata, S. Machida, and K. Horie, J. Polym. Sci. B 37, 2173 (1999)], with each term governed by the dye spacer length. A minimum in broadening and loss-concentration slope at a spacer length of four carbons per alkyl at all wavelengths has important consequences for practical waveguide devices, and is of higher aspect ratio than the spherical limit shown by Robinson and Dalton to minimize dipole interactions under a poling field.
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Affiliation(s)
- Richard R Barto
- Department of Materials Science and Engineering, Stanford University and Lockheed Martin Space Systems Company, Palo Alto, California 94304, USA.
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Barto RR, Frank CW, Bedworth PV, Ermer S, Taylor RE. Near-Infrared Optical Absorption Behavior in High-β Nonlinear Optical Chromophore−Polymer Guest−Host Materials. 1. Continuum Dielectric Effects in Polycarbonate Hosts. J Phys Chem B 2004. [DOI: 10.1021/jp037239x] [Citation(s) in RCA: 13] [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] [Indexed: 11/29/2022]
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Grundy RG, Hutton C, Middleton H, Imeson J, Pritchard J, Kelsey A, Marsden HB, Vujanic GM, Taylor RE. Outcome of patients with stage III or inoperable WT treated on the second United Kingdom WT protocol (UKWT2); a United Kingdom Children's Cancer Study Group (UKCCSG) study. Pediatr Blood Cancer 2004; 42:311-9. [PMID: 14966826 DOI: 10.1002/pbc.10477] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
BACKGROUND The aims of UKWT2 included consolidating the results for stage III patients obtained in UKWT1 and improving the outcome for patients with inoperable tumours by giving vincristine, actinomycin-D and doxorubicin in an intensive schedule (Intensive AVA). PROCEDURE The second UK WT trial (UKWT2) ran between July 1986 and September 1991 accruing 448 patients. One hundred and six patients were diagnosed and treated for stage III disease. Six had clear cell sarcoma of the kidney (CCSK) and seven had rhabdoid tumours of the kidney (RTK) and are analysed separately. One other patient was excluded from overall analysis. Ninety-two patients were followed for a median of 115 months. Seventy-five received standard chemotherapy and abdominal radiotherapy according to protocol. Seventeen had stage III disease at immediate nephrectomy, but radiotherapy was omitted by physician choice. Thirty-three patients had inoperable disease at diagnosis and received pre-nephrectomy chemotherapy. RESULTS Overall survival (OS) at 4 years for stage III favourable histology (FH) patients receiving abdominal RT was 83% (CI: 73-89). For children with stage III disease in whom RT was omitted the OS was 82% (CI: 59-97) and for inoperable disease 94% (CI: 78-98). The overall and event-free survival (EFS) of children with stage III CCSK was 100% and was achieved with the majority of patients not receiving radiotherapy (CI: 48-100). Three of seven children with RTK are alive EFS and OS 43% (CI: 10-73). For patients treated by abdominal radiotherapy the overall local control rate was 94.4% (CI: 86.4-98.5*%), 96.7% (CI: 88.5-99.6%) for flank RT and 83.3% (51.6-98.0%) for whole abdominal radiotherapy (WRT). CONCLUSIONS The outcome for stage III FH disease was similar to that reported for UKWT1 and NWTS-3. The combination of abdominal RT together with 3-drug chemotherapy achieves a high abdominal tumour control rate. Flank RT is probably sufficient for localised tumour rupture. The high cure rates for children in this trial with 'inoperable disease' suggests that treatment should be modified according to their post-chemotherapy stage in order to avoid over-treatment. The high OS for stage III CCSK on this protocol suggests that treatment duration could be curtailed and the role of RT reviewed, though the numbers are small. The prognosis for older children with RTK seems to be better than for younger children although larger studies are required to confirm this.
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Affiliation(s)
- R G Grundy
- Institute of Child Health, University of Birmingham, Whittall Street Birmingham, United Kingdom.
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Bookman EB, Taylor RE, Adams-Campbell L, Kittles RA. DRD4 promoter SNPs and gender effects on Extraversion in African Americans. Mol Psychiatry 2003; 7:786-9. [PMID: 12192624 DOI: 10.1038/sj.mp.4001075] [Citation(s) in RCA: 43] [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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/02/2001] [Revised: 01/03/2002] [Accepted: 01/08/2002] [Indexed: 11/08/2022]
Abstract
There is strong evidence for genetic influences on personality traits. Interest in one such gene, the dopamine D4 receptor (DRD4) grew after an exon III polymorphism was associated with Novelty Seeking and related measures of Extraversion. However, the findings were not confirmed in later studies. Recently, a -521C/T single nucleotide polymorphism (SNP) within the promoter region of the DRD4 gene was found to be related to Novelty Seeking scores in populations from Japan and Hungary. Since little is known about the role DRD4 plays in personality in other populations we evaluated if two DRD4 promoter SNPs, -521C/T and -616C/G, were related to personality traits in African Americans. Personality traits were measured by the NEO-FFI in 71 unrelated African Americans. Genotyping was performed using PCR-RFLP. Multivariate analyses of variance (MANOVA) were performed to evaluate the effects of gender and -616 and -521 genotypes on personality traits. A significant three-way interaction effect from gender, -616 genotype, and -521 genotype was observed for Extraversion scores (F(1,54) 5.86, P < 0.02). Subsequent analyses revealed that the association was mainly due to -521C/T genotype among females (P = 0.01). This study provides further evidence that genetic variation within the DRD4 promoter and gender differences contribute to variation in Novelty Seeking behaviors such as Extraversion.
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Affiliation(s)
- E B Bookman
- Department of Genetics and Human Genetics, Howard University, Washington, DC 20060, USA
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Abstract
Radiotherapy plays an important role in the management of children with cancer. The aim is to achieve local tumour control while minimizing long-term effects. In the treatment of tumours of the central nervous system (CNS) the most important long-term effects are neuropsychological. Elsewhere orthopaedic long-term effects may compromise function or be cosmetically harmful. Proton therapy has the potential for homogeneous irradiation of the target volume while reducing the magnitude and/or extent of the low dose area outside the target volume. This may be clinically relevant for long-term effects in children. Proton radiotherapy has an established role in the treatment of children with chordomas and chondrosarcomas of the base of skull. Planning studies have demonstrated the potential for improving the therapeutic ratio for radiotherapy for tumours of the central nervous system by achieving a uniform dose within the target volume while minimizing the severity of neuropsychological sequelae. Clinical experience of proton radiotherapy for children remains limited with potential areas for clinical research.
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Murphy EG, Barone GJ, Taylor RE. Kilovoltage measurements on diagnostic X-ray machines with voltage dividers. Phys Med Biol 2002. [DOI: 10.1088/0031-9155/17/6/026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Sutter B, Taylor RE, Hossner LR, Ming DW. Solid state 31phosphorus nuclear magnetic resonance of iron-, manganese-, and copper-containing synthetic hydroxyapatites. Soil Sci Soc Am J 2002; 66:455-463. [PMID: 12088032] [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] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The incorporation of micronutrients into synthetic hydroxyapatite (SHA) is proposed for slow release of these nutrients to crops in the National Aeronautics and Space Administration's (NASA's) Advanced Life Support (ALS) program for Lunar or Martian outposts. Solid state 31P nuclear magnetic resonance (NMR) was utilized to examine the paramagnetic effects of Fe3+, Mn2+, and Cu2+ to determine if they were incorporated into the SHA structure. Separate Fe3+, Mn2+, and Cu2+ containing SHA materials along with a transition metal free SHA (pure-SHA) were synthesized using a precipitation method. The proximity (<1 nm) of the transition metals to the 31P nuclei of SHA were apparent when comparing the integrated 31P signal intensities of the pure-SHA (87 arbitrary units g-1) with the Fe-, Mn-, and Cu-SHA materials (37-71 arbitrary units g-1). The lower integrated 31P signal intensities of the Fe-, Mn-, and Cu-SHA materials relative to the pure-SHA suggested that Fe3+, Mn2+, and Cu2+ were incorporated in the SHA structure. Further support for Fe3+, Mn2+, and Cu2+ incorporation was demonstrated by the reduced spin-lattice relaxation constants of the Fe-, Mn-, and Cu-SHA materials (T'=0.075-0.434s) relative to pure-SHA (T1=58.4s). Inversion recovery spectra indicated that Fe3+, Mn2+, and Cu2+ were not homogeneously distributed about the 31P nuclei in the SHA structure. Extraction with diethylene-triamine-penta-acetic acid (DTPA) suggested that between 50 and 80% of the total starting metal concentrations were incorporated in the SHA structure. Iron-, Mn-, and Cu-containing SHA are potential slow release sources of Fe, Mn, and Cu in the ALS cropping system.
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Affiliation(s)
- B Sutter
- National Research Council, NASA, Ames Research Center, Moffett Field, CA 94035, USA.
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Taylor RE. Death of neurasthenia and its psychological reincarnation: a study of neurasthenia at the National Hospital for the Relief and Cure of the Paralysed and Epileptic, Queen Square, London, 1870-1932. Br J Psychiatry 2001; 179:550-7. [PMID: 11731361 DOI: 10.1192/bjp.179.6.550] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
BACKGROUND The diagnosis of neurasthenia appeared in 1869 and rapidly became fashionable and highly prevalent. It disappeared almost completely, producing ongoing debates about what happened to the disease, which have not so far been informed by empirical data. AIMS To use empirical historical hospital data from one specific hospital to explore several controversies about neurasthenia, including what happened to the disorder. METHOD The annual reports of Queen Square Hospital were examined from 1870 to 1947. The prevalence of neurasthenia diagnoses as a proportion of total discharges was recorded. The possible diagnostic categories into which neurasthenia could have been reclassified were identified. Textbooks and writing by neurologists working at the hospital during this period were examined. RESULTS Neurasthenia accounted for 6-11% of total discharges from the late 1890s to 1930, when it virtually disappeared. Men accounted for 33-50% of cases. CONCLUSIONS Neurasthenia affected both the upper and working classes and both men and women. Neurologists, not psychiatrists, continued to see the disorder well into the 20th century. Neurasthenia did not disappear, but was reclassified into psychological diagnoses.
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Affiliation(s)
- R E Taylor
- Department of Psychiatry, St Bartholomew's and the Royal London School of Medicine and Dentistry, Basic Medical Sciences Building, Queen Mary and Westfield College, Mile End Road, London El 4NS, UK
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Akinshola BE, Stewart RR, Karvonen LL, Taylor RE, Liesi P. Involvement of non-NMDA receptors in the rescue of weaver cerebellar granule neurons and sensitivity to ethanol of cerebellar AMPA receptors in oocytes. Brain Res Mol Brain Res 2001; 93:8-17. [PMID: 11532333 DOI: 10.1016/s0169-328x(01)00152-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
The cellular mechanism responsible for the death of cerebellar granule neurons in the weaver mutant mouse is still being intensely investigated. To determine if alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) glutamate receptors are involved in producing the weaver phenotype or are altered by the weaver gene, we used (1) reverse transcription and polymerase chain reaction (RT-PCR) to detect transcripts of glutamate receptors (GluR1-4) from wild-type and mutant cerebella; (2) immunocytochemistry to establish the types of glutamate receptors present in granule neurons cultured from normal and homozygous weaver postnatal day 5-6 (P5-6) cerebella; (3) 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX), a blocker of glutamate (AMPA/Kainate/NMDA) receptors, and 6,7-dinitroquinoxaline-2,3-dione (NBQX), a blocker of AMPA and kainate receptors, to assess the number of neurons and the number of neurons with long neurites in cultures of homozygous weaver granule neurons; (4) two-electrode voltage clamp recordings to study AMPA glutamate receptor expression in Xenopus oocytes after injection of mRNA isolated from cerebella of normal and weaver P5-6, postnatal day 10 (P10) and postnatal day 23 (P23) mice; and (5) ethanol, which at low 1-10 mM concentrations had been shown previously to rescue homozygous weaver granule neurons in culture [Liesi et al., J. Neurosci. Res. 48 (1997) 571-579], to examine its effect on modulation of AMPA receptors expressed from mRNA. By RT-PCR, the mRNA coding for AMPA receptor subunits GluR1-4 were detected from +/+ and wv/wv cerebella, and by immunocytochemistry, GluR1, GluR2/3 and GluR4 were observed to be expressed in cultured +/+ and wv/wv granule cells. CNQX at 10 microM or NBQX at 10 microM significantly increased the number of surviving neurons and the number with long neurites as compared to wv/wv controls. In addition, CNQX was significantly more effective than NBQX. In oocytes injected with mRNA from P10 normal or weaver cerebella, the amplitudes of the responses to kainate were about equal. In contrast, the amplitudes of the kainate-activated currents in oocytes injected with weaver P23 mRNA were about twice as large as the currents observed in oocytes injected with mRNA from normal P23 cerebella, and both were larger than kainate-activated currents observed after injection of P10 normal and weaver mRNA. Kainate-activated AMPA receptor currents in oocytes injected with mRNA from P10 and P23 normal and homozygous weaver cerebella were inhibited by ethanol. There were no significant differences in the inhibition produced by ethanol on currents from P10 or P23 normal and wv/wv mRNA. Thus, P23 weaver cerebellar mRNA expressed more kainate-activated current in oocytes than P23 normal cerebellar mRNA; both normal and weaver cerebellar granule neurons express mRNA coding for functional AMPA receptors that are susceptible to ethanol inhibition.
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Affiliation(s)
- B E Akinshola
- Department of Pharmacology, Howard University College of Medicine, Suite 3408 NPG Adams Bldg., 520 W. Street N.W., Washington, DC 20059, USA.
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Abstract
[reaction: see text] Homoallylic alcohols with anti-allylic substituents display enhanced E-olefin selectivity in cross-metathesis (CM) reactions with allyltrimethylsilane. The high selectivity can be explained via a five-membered chelate intermediate in which the hydroxyl group of the homoallylic alcohol coordinates to the ruthenium metal center of Grubbs' catalyst.
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Affiliation(s)
- F C Engelhardt
- Department of Chemistry and Biochemistry, 251 Nieuwland Science Hall, University of Notre Dame, Notre Dame, Indiana 46556-5670, USA
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Abstract
[reaction: see text] A highly convergent total synthesis of the natural products epothilone B and D is described. The route is highlighted by efficient generation of a C12-C13 trisubstituted olefin which exploits a sequential Nozaki-Hiyama-Kishi coupling and a stereoselective thionyl chloride rearrangement.
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Affiliation(s)
- R E Taylor
- Department of Chemistry & Biochemistry, University of Notre Dame, 251 Nieuwland Science Hall, Notre Dame, Indiana 46556-5670, USA.
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Darensbourg DJ, Wildeson JR, Yarbrough JC, Taylor RE. Tricyclohexylphosphine derivatives of bis(2,6-difluorophenoxide)cadmium: a solution and solid-state NMR study. Inorg Chem 2001; 40:3639-42. [PMID: 11421721 DOI: 10.1021/ic010104q] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- D J Darensbourg
- Department of Chemistry, Texas A&M University, P.O. Box 30012, College Station, Texas 77842, USA
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