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Young AT, Deal H, Rusch G, Pozdin VA, Brown AC, Daniele M. Simple Design for Membrane-Free Microphysiological Systems to Model the Blood-Tissue Barriers. bioRxiv 2023:2023.10.20.563328. [PMID: 37961220 PMCID: PMC10634696 DOI: 10.1101/2023.10.20.563328] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2023]
Abstract
Microphysiological systems (MPS) incorporate physiologically relevant microanatomy, mechanics, and cells to mimic tissue function. Reproducible and standardized in vitro models of tissue barriers, such as the blood-tissue interface (BTI), are critical for next-generation MPS applications in research and industry. Many models of the BTI are limited by the need for semipermeable membranes, use of homogenous cell populations, or 2D culture. These factors limit the relevant endothelial-epithelial contact and 3D transport, which would best mimic the BTI. Current models are also difficult to assemble, requiring precise alignment and layering of components. The work reported herein details the engineering of a BTI-on-a-chip (BTI Chip) that addresses current disadvantages by demonstrating a single layer, membrane-free design. Laminar flow profiles, photocurable hydrogel scaffolds, and human cell lines were used to construct a BTI Chip that juxtaposes an endothelium in direct contact with a 3D engineered tissue. A biomaterial composite, gelatin methacryloyl and 8-arm polyethylene glycol thiol, was used for in situ fabrication of a tissue structure within a Y-shaped microfluidic device. To produce the BTI, a laminar flow profile was achieved by flowing a photocurable precursor solution alongside phosphate buffered saline. Immediately after stopping flow, the scaffold underwent polymerization through a rapid exposure to UV light (<300 mJ·cm-2). After scaffold formation, blood vessel endothelial cells were introduced and allowed to adhere directly to the 3D tissue scaffold, without barriers or phase guides. Fabrication of the BTI Chip was demonstrated in both an epithelial tissue model and blood-brain barrier (BBB) model. In the epithelial model, scaffolds were seeded with human dermal fibroblasts. For the BBB models, scaffolds were seeded with the immortalized glial cell line, SVGP12. The BTI Chip microanatomy was analyzed post facto by immunohistochemistry, showing the uniform production of a patent endothelium juxtaposed with a 3D engineered tissue. Fluorescent tracer molecules were used to characterize the permeability of the BTI Chip. The BTI Chips were challenged with an efflux pump inhibitor, cyclosporine A, to assess physiological function and endothelial cell activation. Operation of physiologically relevant BTI Chips and a novel means for high-throughput MPS generation was demonstrated, enabling future development for drug candidate screening and fundamental biological investigations.
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Affiliation(s)
- Ashlyn T. Young
- Joint Department of Biomedical Engineering, North Carolina State University and University of North Carolina, Chapel Hill, 911 Oval Dr., Raleigh NC, 27695 (USA)
| | - Halston Deal
- Joint Department of Biomedical Engineering, North Carolina State University and University of North Carolina, Chapel Hill, 911 Oval Dr., Raleigh NC, 27695 (USA)
- Comparative Medicine Institute, North Carolina State University, 1060 William Moore Dr., Raleigh, NC 27606, USA
| | - Gabrielle Rusch
- Joint Department of Biomedical Engineering, North Carolina State University and University of North Carolina, Chapel Hill, 911 Oval Dr., Raleigh NC, 27695 (USA)
- Comparative Medicine Institute, North Carolina State University, 1060 William Moore Dr., Raleigh, NC 27606, USA
| | - Vladimir A. Pozdin
- Department of Electrical & Computer Engineering, Florida International University, Miami, FL (USA)
- Department of Mechanical & Materials Engineering, Florida International University, Miami, FL (USA)
| | - Ashley C. Brown
- Joint Department of Biomedical Engineering, North Carolina State University and University of North Carolina, Chapel Hill, 911 Oval Dr., Raleigh NC, 27695 (USA)
- Comparative Medicine Institute, North Carolina State University, 1060 William Moore Dr., Raleigh, NC 27606, USA
| | - Michael Daniele
- Joint Department of Biomedical Engineering, North Carolina State University and University of North Carolina, Chapel Hill, 911 Oval Dr., Raleigh NC, 27695 (USA)
- Comparative Medicine Institute, North Carolina State University, 1060 William Moore Dr., Raleigh, NC 27606, USA
- Department of Mechanical & Materials Engineering, Florida International University, Miami, FL (USA)
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Roosa CA, Muhamed I, Young AT, Nellenbach K, Daniele MA, Ligler FS, Brown AC. Synthesis of sonicated fibrin nanoparticles that modulate fibrin clot polymerization and enhance angiogenic responses. Colloids Surf B Biointerfaces 2021; 204:111805. [PMID: 33964527 PMCID: PMC8217261 DOI: 10.1016/j.colsurfb.2021.111805] [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: 12/31/2020] [Revised: 04/09/2021] [Accepted: 04/26/2021] [Indexed: 10/21/2022]
Abstract
Chronic wounds can occur when the healing process is disrupted and the wound remains in a prolonged inflammatory stage that leads to severe tissue damage and poor healing outcomes. Clinically used treatments, such as high density, FDA-approved fibrin sealants, do not provide an optimal environment for native cell proliferation and subsequent tissue regeneration. Therefore, new treatments outside the confines of these conventional fibrin bulk gel therapies are required. We have previously developed flowable, low-density fibrin nanoparticles that, when coupled to keratinocyte growth factor, promote cell migration and epithelial wound closure in vivo. Here, we report a new high throughput method for generating the fibrin nanoparticles using probe sonication, which is less time intensive than the previously reported microfluidic method, and investigate the ability of the sonicated fibrin nanoparticles (SFBN) to promote clot formation and cell migration in vitro. The SFBNs can form a fibrin gel when combined with fibrinogen in the absence of exogenous thrombin, and the polymerization rate and fiber density in these fibrin clots is tunable based on SFBN concentration. Furthermore, fibrin gels made with SFBNs support cell migration in an in vitro angiogenic sprouting assay, which is relevant for wound healing. In this report, we show that SFBNs may be a promising wound healing therapy that can be easily produced and delivered in a flowable formulation.
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Affiliation(s)
- Colleen A Roosa
- Joint Department of Biomedical Engineering, NC State University and UNC Chapel-Hill, Raleigh, NC, United States; Comparative Medicine Institute, NC State University, Raleigh, NC, United States
| | - Ismaeel Muhamed
- Joint Department of Biomedical Engineering, NC State University and UNC Chapel-Hill, Raleigh, NC, United States; Comparative Medicine Institute, NC State University, Raleigh, NC, United States
| | - Ashlyn T Young
- Joint Department of Biomedical Engineering, NC State University and UNC Chapel-Hill, Raleigh, NC, United States; Comparative Medicine Institute, NC State University, Raleigh, NC, United States
| | - Kimberly Nellenbach
- Joint Department of Biomedical Engineering, NC State University and UNC Chapel-Hill, Raleigh, NC, United States; Comparative Medicine Institute, NC State University, Raleigh, NC, United States
| | - Michael A Daniele
- Joint Department of Biomedical Engineering, NC State University and UNC Chapel-Hill, Raleigh, NC, United States; Comparative Medicine Institute, NC State University, Raleigh, NC, United States; Department of Electrical and Computer Engineering, NC State University, Raleigh, NC, United States
| | - Frances S Ligler
- Joint Department of Biomedical Engineering, NC State University and UNC Chapel-Hill, Raleigh, NC, United States; Comparative Medicine Institute, NC State University, Raleigh, NC, United States
| | - Ashley C Brown
- Joint Department of Biomedical Engineering, NC State University and UNC Chapel-Hill, Raleigh, NC, United States; Comparative Medicine Institute, NC State University, Raleigh, NC, United States.
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Day K, Schneible JD, Young AT, Pozdin VA, Van Den Driessche G, Gaffney LA, Prodromou R, Freytes DO, Fourches D, Daniele M, Menegatti S. Photoinduced reconfiguration to control the protein-binding affinity of azobenzene-cyclized peptides. J Mater Chem B 2021; 8:7413-7427. [PMID: 32661544 DOI: 10.1039/d0tb01189d] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The impact of next-generation biorecognition elements (ligands) will be determined by the ability to remotely control their binding activity for a target biomolecule in complex environments. Compared to conventional mechanisms for regulating binding affinity (pH, ionic strength, or chaotropic agents), light provides higher accuracy and rapidity, and is particularly suited for labile targets. In this study, we demonstrate a general method to develop azobenzene-cyclized peptide ligands with light-controlled affinity for target proteins. Light triggers a cis/trans isomerization of the azobenzene, which results in a major structural rearrangement of the cyclic peptide from a non-binding to a binding configuration. Critical to this goal are the ability to achieve efficient photo-isomerization under low light dosage and the temporal stability of both cis and trans isomers. We demonstrated our method by designing photo-switchable peptides targeting vascular cell adhesion marker 1 (VCAM1), a cell marker implicated in stem cell function. Starting from a known VCAM1-binding linear peptide, an ensemble of azobenzene-cyclized variants with selective light-controlled binding were identified by combining in silico design with experimental characterization via spectroscopy and surface plasmon resonance. Variant cycloAZOB[G-VHAKQHRN-K] featured rapid, light-controlled binding of VCAM1 (KD,trans/KD,cis ∼ 130). Biotin-cycloAZOB[G-VHAKQHRN-K] was utilized to label brain microvascular endothelial cells (BMECs), showing co-localization with anti-VCAM1 antibodies in cis configuration and negligible binding in trans configuration.
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Affiliation(s)
- Kevin Day
- Department of Chemical and Biomolecular Engineering, North Carolina State University, 911 Partners Way, Raleigh, North Carolina, USA.
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Abstract
Herein, a 60-electrode array is fabricated down the length of a microchamber for analysis of a microphysiological system. The electrode array is fabricated by standard photolithographic, metallization, and etching techniques. Permutations of 2-wire impedance measurements (10 Hz to 1 MHz) are made along the length of the microchannel using a multiplexer, Gamry potentiostat, and custom Labview code. An impedance "heat map" is created via custom algorithms. Spatial resolution and mapping capabilities are exhibited using conductive NaCl solutions and 2D cell culture.
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Affiliation(s)
- Ashlyn T Young
- Joint Department of Biomedical Engineering, NC State University and UNC at Chapel Hill, Raleigh, NC, USA
| | - Vladimir A Pozdin
- Department of Electrical and Computer Engineering, Florida International University, Miami, FL, USA
| | - Michael Daniele
- Joint Department of Biomedical Engineering, NC State University and UNC at Chapel Hill, Raleigh, NC, USA.,Department of Electrical and Computer Engineering, NC State University, Raleigh, NC, USA
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Young AT, White OC, Daniele MA. Rheological Properties of Coordinated Physical Gelation and Chemical Crosslinking in Gelatin Methacryloyl (GelMA) Hydrogels. Macromol Biosci 2020; 20:e2000183. [PMID: 32856384 DOI: 10.1002/mabi.202000183] [Citation(s) in RCA: 50] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2020] [Revised: 08/13/2020] [Indexed: 12/18/2022]
Abstract
Synthetically modified proteins, such as gelatin methacryloyl (GelMA), are growing in popularity for bioprinting and biofabrication. GelMA is a photocurable macromer that can rapidly form hydrogels, while also presenting bioactive peptide sequences for cellular adhesion and proliferation. The mechanical properties of GelMA are highly tunable by modifying the degree of substitution via synthesis conditions, though the effects of source material and thermal gelation have not been comprehensively characterized for lower concentration gels. Herein, the effects of animal source and processing sequence are investigated on scaffold mechanical properties. Hydrogels of 4-6 wt% are characterized. Depending on the temperature at crosslinking, the storage moduli for GelMA derived from pigs, cows, and cold-water fish range from 723 to 7340 Pa, 516 to 3484 Pa, and 294 to 464 Pa, respectively. The maximum storage moduli are achieved only by coordinated physical gelation and chemical crosslinking. In this method, the classic thermo-reversible gelation of gelatin occurs when GelMA is cooled below a thermal transition temperature, which is subsequently "locked in" by chemical crosslinking via photocuring. The effects of coordinated physical gelation and chemical crosslinking are demonstrated by precise photopatterning of cell-laden microstructures, inducing different cellular behavior depending on the selected mechanical properties of GelMA.
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Affiliation(s)
- Ashlyn T Young
- Joint Department of Biomedical Engineering, North Carolina State University and University of North Carolina, Chapel Hill, 911 Oval Dr., Raleigh, NC, 27695, USA
| | - Olivia C White
- Department of Electrical & Computer Engineering, North Carolina State University, 890 Oval Dr., Raleigh, NC, 27695, USA
| | - Michael A Daniele
- Joint Department of Biomedical Engineering, North Carolina State University and University of North Carolina, Chapel Hill, 911 Oval Dr., Raleigh, NC, 27695, USA.,Department of Electrical & Computer Engineering, North Carolina State University, 890 Oval Dr., Raleigh, NC, 27695, USA
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Schneible JD, Young AT, Daniele MA, Menegatti S. Chitosan Hydrogels for Synergistic Delivery of Chemotherapeutics to Triple Negative Breast Cancer Cells and Spheroids. Pharm Res 2020; 37:142. [PMID: 32661774 PMCID: PMC7983306 DOI: 10.1007/s11095-020-02864-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [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: 05/12/2020] [Accepted: 06/23/2020] [Indexed: 02/07/2023]
Abstract
PURPOSE This study aimed to develop a hydrogel system for treating aggressive triple negative breast cancer (TNBC) via kinetically-controlled delivery of the synergistic drug pair doxorubicin (DOX) and gemcitabine (GEM). A 2D assay was adopted to evaluate therapeutic efficacy by determining combination index (CI), and a 3D assay using cancer spheroids was implemented to assess the potential for translation in vivo. METHODS The release of DOX and GEM from an acetylated-chitosan (ACS, degree of acetylation χAc = 40 ± 5%) was characterized to identify a combined drug loading that affords release kinetics and dose that are therapeutically synergistic. The selected DOX/GEM-ACS formulation was evaluated in vitro with 2-D and 3-D models of TNBC to determine the combination index (CI) and the tumor volume reduction, respectively. RESULTS Therapeutically desired release dosages and kinetics of GEM and DOX were achieved. When evaluated with a 2-D model of TNBC, the hydrogel afforded a CI of 0.14, indicating a stronger synergism than concurrent administration of DOX and GEM (CI = 0.23). Finally, the therapeutic hydrogel accomplished a notable volume reduction of the cancer spheroids (up to 30%), whereas the corresponding dosages of free drugs only reduced growth rate. CONCLUSIONS The ACS hydrogel delivery system accomplishes drug release kinetics and molar ratio that affords strong therapeutically synergism. These results, in combination with the choice of ACS as affordable and highly abundant source material, provide a strong pre-clinical demonstration of the potential of the proposed system for complementing surgical resection of aggressive solid tumors.
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Affiliation(s)
- John D Schneible
- Department of Chemical and Biomolecular Engineering, North Carolina State University, 911 Partners Way, Raleigh, North Carolina, USA
| | - Ashlyn T Young
- Joint Department of Biomedical Engineering, North Carolina State University and University of North Carolina, Chapel Hill, North Carolina, USA
| | - M A Daniele
- Joint Department of Biomedical Engineering, North Carolina State University and University of North Carolina, Chapel Hill, North Carolina, USA.
- Department of Electrical and Computer Engineering, North Carolina State University, 890 Oval Drive, Raleigh, North Carolina, USA.
| | - S Menegatti
- Department of Chemical and Biomolecular Engineering, North Carolina State University, 911 Partners Way, Raleigh, North Carolina, USA.
- Biomanufacturing Training and Education Center, North Carolina State University, 850 Oval Dr, Raleigh, North Carolina, USA.
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Schneible JD, Shi K, Young AT, Ramesh S, He N, Dowdey CE, Dubnansky JM, Lilova RL, Gao W, Santiso E, Daniele M, Menegatti S. Modified gaphene oxide (GO) particles in peptide hydrogels: a hybrid system enabling scheduled delivery of synergistic combinations of chemotherapeutics. J Mater Chem B 2020; 8:3852-3868. [PMID: 32219269 PMCID: PMC7945679 DOI: 10.1039/d0tb00064g] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The scheduled delivery of synergistic drug combinations is increasingly recognized as highly effective against advanced solid tumors. Of particular interest are composite systems that release a sequence of drugs with defined kinetics and molar ratios to enhance therapeutic effect, while minimizing the dose to patients. In this work, we developed a homogeneous composite comprising modified graphene oxide (GO) nanoparticles embedded in a Max8 peptide hydrogel, which provides controlled kinetics and molar ratios of release of doxorubicin (DOX) and gemcitabine (GEM). First, modified GO nanoparticles (tGO) were designed to afford high DOX loading and sustained release (18.9% over 72 h and 31.4% over 4 weeks). Molecular dynamics simulations were utilized to model the mechanism of DOX loading as a function of surface modification. In parallel, a Max8 hydrogel was developed to release GEM with faster kinetics and achieve a 10-fold molar ratio to DOX. The selected DOX/tGO nanoparticles were suspended in a GEM/Max8 hydrogel matrix, and the resulting composite was tested against a triple negative breast cancer cell line, MDA-MB-231. Notably, the composite formulation afforded a combination index of 0.093 ± 0.001, indicating a much stronger synergism compared to the DOX-GEM combination co-administered in solution (CI = 0.396 ± 0.034).
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Affiliation(s)
- John D Schneible
- Department of Chemical and Biomolecular Engineering, North Carolina State University, 911 Partners Way, Raleigh, North Carolina, USA.
| | - Kaihang Shi
- Department of Chemical and Biomolecular Engineering, North Carolina State University, 911 Partners Way, Raleigh, North Carolina, USA.
| | - Ashlyn T Young
- Joint Department of Biomedical Engineering, North Carolina State University - University of North Carolina Chapel Hill, North Carolina, USA
| | - Srivatsan Ramesh
- Department of Chemical and Biomolecular Engineering, North Carolina State University, 911 Partners Way, Raleigh, North Carolina, USA.
| | - Nanfei He
- Department of Textile Engineering, Chemistry, and Science, 1020 Main Campus Drive, Raleigh, North Carolina, USA
| | - Clay E Dowdey
- Department of Chemical and Biomolecular Engineering, North Carolina State University, 911 Partners Way, Raleigh, North Carolina, USA.
| | - Jean Marie Dubnansky
- Department of Chemical and Biomolecular Engineering, North Carolina State University, 911 Partners Way, Raleigh, North Carolina, USA.
| | - Radina L Lilova
- Department of Chemical and Biomolecular Engineering, North Carolina State University, 911 Partners Way, Raleigh, North Carolina, USA.
| | - Wei Gao
- Department of Textile Engineering, Chemistry, and Science, 1020 Main Campus Drive, Raleigh, North Carolina, USA
| | - Erik Santiso
- Department of Chemical and Biomolecular Engineering, North Carolina State University, 911 Partners Way, Raleigh, North Carolina, USA.
| | - Michael Daniele
- Joint Department of Biomedical Engineering, North Carolina State University - University of North Carolina Chapel Hill, North Carolina, USA and Department of Electrical and Computer Engineering, North Carolina State University, 890 Oval Drive, Raleigh, North Carolina, USA.
| | - Stefano Menegatti
- Department of Chemical and Biomolecular Engineering, North Carolina State University, 911 Partners Way, Raleigh, North Carolina, USA.
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Young AT, Rivera KR, Erb PD, Daniele MA. Monitoring of Microphysiological Systems: Integrating Sensors and Real-Time Data Analysis toward Autonomous Decision-Making. ACS Sens 2019; 4:1454-1464. [PMID: 30964652 DOI: 10.1021/acssensors.8b01549] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Microphysiological systems replicate human organ function and are promising technologies for discovery of translatable biomarkers, pharmaceuticals, and regenerative therapies. Because microphysiological systems require complex microscale anatomical structures and heterogeneous cell populations, a major challenge remains to manufacture and operate these products with reproducible and standardized function. In this Perspective, three stages of microphysiological system monitoring, including process, development, and function, are assessed. The unique features and remaining technical challenges for the required sensors are discussed. Monitoring of microphysiological systems requires nondestructive, continuous biosensors and imaging techniques. With such tools, the extent of cellular and tissue development, as well as function, can be autonomously determined and optimized by correlating physical and chemical sensor outputs with markers of physiological performance. Ultimately, data fusion and analyses across process, development, and function monitors can be implemented to adopt microphysiological systems for broad research and commercial applications.
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Affiliation(s)
- Ashlyn T. Young
- Joint Department of Biomedical Engineering, North Carolina State University and University of North Carolina, Chapel Hill, 911 Oval Drive, Raleigh, North Carolina 27695, United States
| | - Kristina R. Rivera
- Joint Department of Biomedical Engineering, North Carolina State University and University of North Carolina, Chapel Hill, 911 Oval Drive, Raleigh, North Carolina 27695, United States
| | - Patrick D. Erb
- Joint Department of Biomedical Engineering, North Carolina State University and University of North Carolina, Chapel Hill, 911 Oval Drive, Raleigh, North Carolina 27695, United States
| | - Michael A. Daniele
- Joint Department of Biomedical Engineering, North Carolina State University and University of North Carolina, Chapel Hill, 911 Oval Drive, Raleigh, North Carolina 27695, United States
- Department of Electrical & Computer Engineering, North Carolina State University, 890 Oval Drive, Raleigh, North Carolina 27695, United States
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Su T, Huang K, Ma H, Liang H, Dinh PU, Chen J, Shen D, Allen TA, Qiao L, Li Z, Hu S, Cores J, Frame BN, Young AT, Yin Q, Liu J, Qian L, Caranasos TG, Brudno Y, Ligler FS, Cheng K. Platelet-Inspired Nanocells for Targeted Heart Repair After Ischemia/Reperfusion Injury. Adv Funct Mater 2019; 29:1803567. [PMID: 32256277 PMCID: PMC7111457 DOI: 10.1002/adfm.201803567] [Citation(s) in RCA: 73] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/23/2018] [Indexed: 05/21/2023]
Abstract
Cardiovascular disease is the leading cause of mortality worldwide. While reperfusion therapy is vital for patient survival post-heart attack, it also causes further tissue injury, known as myocardial ischemia/reperfusion (I/R) injury in clinical practice. Exploring ways to attenuate I/R injury is of clinical interest for improving post-ischemic recovery. A platelet-inspired nanocell (PINC) that incorporates both prostaglandin E2 (PGE2)-modified platelet membrane and cardiac stromal cell-secreted factors to target the heart after I/R injury is introduced. By taking advantage of the natural infarct-homing ability of platelet membrane and the overexpression of PGE2 receptors (EPs) in the pathological cardiac microenvironment after I/R injury, the PINCs can achieve targeted delivery of therapeutic payload to the injured heart. Furthermore, a synergistic treatment efficacy can be achieved by PINC, which combines the paracrine mechanism of cell therapy with the PGE2/EP receptor signaling that is involved in the repair and regeneration of multiple tissues. In a mouse model of myocardial I/R injury, intravenous injection of PINCs results in augmented cardiac function and mitigated heart remodeling, which is accompanied by the increase in cycling cardiomyocytes, activation of endogenous stem/progenitor cells, and promotion of angiogenesis. This approach represents a promising therapeutic delivery platform for treating I/R injury.
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Affiliation(s)
- Teng Su
- Joint Department of Biomedical Engineering, University of North Carolina at Chapel Hill and North, Carolina State University, Raleigh, NC 27695, USA
| | - Ke Huang
- Joint Department of Biomedical Engineering, University of North Carolina at Chapel Hill and North, Carolina State University, Raleigh, NC 27695, USA
| | - Hong Ma
- Department of Pathology and Laboratory Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Hongxia Liang
- Department of Molecular Biomedical Sciences and Comparative, Medicine Institute, North Carolina State University, Raleigh, NC 27607, USA
| | - Phuong-Uyen Dinh
- Department of Molecular Biomedical Sciences and Comparative, Medicine Institute, North Carolina State University, Raleigh, NC 27607, USA
| | - Justin Chen
- Joint Department of Biomedical Engineering, University of North Carolina at Chapel Hill and North, Carolina State University, Raleigh, NC 27695, USA
| | - Deliang Shen
- Department of Cardiology, The First Affiliated Hospital of Zhengzhou University Zhengzhou, Henan 450052, China
| | - Tyler A Allen
- Department of Molecular Biomedical Sciences and Comparative, Medicine Institute, North Carolina State University, Raleigh, NC 27607, USA
| | - Li Qiao
- Department of Molecular Biomedical Sciences and Comparative, Medicine Institute, North Carolina State University, Raleigh, NC 27607, USA
| | - Zhenhua Li
- Department of Molecular Biomedical Sciences and Comparative, Medicine Institute, North Carolina State University, Raleigh, NC 27607, USA
| | - Shiqi Hu
- Department of Molecular Biomedical Sciences and Comparative, Medicine Institute, North Carolina State University, Raleigh, NC 27607, USA
| | - Jhon Cores
- Joint Department of Biomedical Engineering, University of North Carolina at Chapel Hill and North, Carolina State University, Raleigh, NC 27695, USA
| | - Brianna N Frame
- Division of Cardiothoracic Surgery, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Ashlyn T Young
- Joint Department of Biomedical Engineering, University of North Carolina at Chapel Hill and North, Carolina State University, Raleigh, NC 27695, USA
| | - Qi Yin
- Department of Molecular Biomedical Sciences and Comparative, Medicine Institute, North Carolina State University, Raleigh, NC 27607, USA
| | - Jiandong Liu
- Department of Pathology and Laboratory Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Li Qian
- Department of Pathology and Laboratory Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Thomas G Caranasos
- Division of Cardiothoracic Surgery, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Yevgeny Brudno
- Joint Department of Biomedical Engineering, University of North Carolina at Chapel Hill and North, Carolina State University, Raleigh, NC 27695, USA
| | - Frances S Ligler
- Joint Department of Biomedical Engineering, University of North Carolina at Chapel Hill and North, Carolina State University, Raleigh, NC 27695, USA
| | - Ke Cheng
- Joint Department of Biomedical Engineering, University of North Carolina at Chapel Hill and North, Carolina State University, Raleigh, NC 27695, USA
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Su T, Huang K, Daniele MA, Hensley MT, Young AT, Tang J, Allen TA, Vandergriff AC, Erb PD, Ligler FS, Cheng K. Cardiac Stem Cell Patch Integrated with Microengineered Blood Vessels Promotes Cardiomyocyte Proliferation and Neovascularization after Acute Myocardial Infarction. ACS Appl Mater Interfaces 2018; 10:33088-33096. [PMID: 30188113 PMCID: PMC6376980 DOI: 10.1021/acsami.8b13571] [Citation(s) in RCA: 50] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
Cardiac stem cell (CSC) therapy has shown preclinical and clinical evidence for ischemic heart repair but is limited by low cellular engraftment and survival after transplantation. Previous versions of the cardiac patch strategy improve stem cell engraftment and encourage repair of cardiac tissue. However, cardiac patches that can enhance cardiomyogenesis and angiogenesis at the injured site remain elusive. Therapies that target cardiomyocyte proliferation and new blood vessel formation hold great potential for the protection against acute myocardial infarction (MI). Here, we report a new strategy for creating a vascularized cardiac patch in a facile and modular fashion by leveraging microfluidic hydrodynamic focusing to construct the biomimetic microvessels (BMVs) that include human umbilical vein endothelial cells (HUVECs) lining the luminal surface and then encapsulating the BMVs in a fibrin gel spiked with human CSCs. We show that the endothelialized BMVs mimicked the natural architecture and function of capillaries and that the resultant vascularized cardiac patch (BMV-CSC patch) exhibited equivalent release of paracrine factors compared to those of coculture of genuine human CSCs and HUVECs after 7 days of in vitro culture. In a rat model of acute MI, the BMV-CSC patch therapy induced profound mitotic activities of cardiomyocytes in the peri-infarct region 4 weeks post-treatment. A significant increase in myocardial capillary density was noted in the infarcted hearts that received BMV-CSC patch treatment compared to the infarcted hearts treated with conventional CSC patches. The striking therapeutic benefits and the fast and facile fabrication of the BMV-CSC patch make it promising for practical applications. Our findings suggest that the BMV-CSC patch strategy may open up new possibilities for the treatment of ischemic heart injury.
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Affiliation(s)
- Teng Su
- Joint Department of Biomedical Engineering, University of North Carolina at Chapel Hill and North Carolina State University, Raleigh, North Carolina 27695, United States
- Department of Molecular Biomedical Sciences and Comparative Medicine Institute, North Carolina State University, 1060 William Moore Drive, Raleigh, North Carolina 27607, United States
| | - Ke Huang
- Joint Department of Biomedical Engineering, University of North Carolina at Chapel Hill and North Carolina State University, Raleigh, North Carolina 27695, United States
- Department of Electrical and Computer Engineering, North Carolina State University, Raleigh, North Carolina 27695, United States
| | - Michael A. Daniele
- Joint Department of Biomedical Engineering, University of North Carolina at Chapel Hill and North Carolina State University, Raleigh, North Carolina 27695, United States
- Department of Electrical and Computer Engineering, North Carolina State University, Raleigh, North Carolina 27695, United States
| | - Michael Taylor Hensley
- Joint Department of Biomedical Engineering, University of North Carolina at Chapel Hill and North Carolina State University, Raleigh, North Carolina 27695, United States
- Department of Molecular Biomedical Sciences and Comparative Medicine Institute, North Carolina State University, 1060 William Moore Drive, Raleigh, North Carolina 27607, United States
| | - Ashlyn T. Young
- Joint Department of Biomedical Engineering, University of North Carolina at Chapel Hill and North Carolina State University, Raleigh, North Carolina 27695, United States
| | - Junnan Tang
- Department of Molecular Biomedical Sciences and Comparative Medicine Institute, North Carolina State University, 1060 William Moore Drive, Raleigh, North Carolina 27607, United States
- Department of Cardiology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan 450052, China
| | - Tyler A. Allen
- Joint Department of Biomedical Engineering, University of North Carolina at Chapel Hill and North Carolina State University, Raleigh, North Carolina 27695, United States
- Department of Molecular Biomedical Sciences and Comparative Medicine Institute, North Carolina State University, 1060 William Moore Drive, Raleigh, North Carolina 27607, United States
| | - Adam C. Vandergriff
- Joint Department of Biomedical Engineering, University of North Carolina at Chapel Hill and North Carolina State University, Raleigh, North Carolina 27695, United States
- Department of Molecular Biomedical Sciences and Comparative Medicine Institute, North Carolina State University, 1060 William Moore Drive, Raleigh, North Carolina 27607, United States
| | - Patrick D. Erb
- Joint Department of Biomedical Engineering, University of North Carolina at Chapel Hill and North Carolina State University, Raleigh, North Carolina 27695, United States
| | - Frances S. Ligler
- Joint Department of Biomedical Engineering, University of North Carolina at Chapel Hill and North Carolina State University, Raleigh, North Carolina 27695, United States
| | - Ke Cheng
- Joint Department of Biomedical Engineering, University of North Carolina at Chapel Hill and North Carolina State University, Raleigh, North Carolina 27695, United States
- Department of Molecular Biomedical Sciences and Comparative Medicine Institute, North Carolina State University, 1060 William Moore Drive, Raleigh, North Carolina 27607, United States
- Divison of Pharmacoengineering and Molecular Pharmaceutics, Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
- Corresponding Author:, . Phone: 919 513 6157. Fax: 919 513 7301
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11
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Rivera KR, Pozdin VA, Young AT, Erb PD, Wisniewski NA, Magness ST, Daniele M. Integrated phosphorescence-based photonic biosensor (iPOB) for monitoring oxygen levels in 3D cell culture systems. Biosens Bioelectron 2018; 123:131-140. [PMID: 30060990 DOI: 10.1016/j.bios.2018.07.035] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [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: 05/01/2018] [Revised: 07/13/2018] [Accepted: 07/16/2018] [Indexed: 12/16/2022]
Abstract
Physiological processes, such as respiration, circulation, digestion, and many pathologies alter oxygen concentration in the blood and tissue. When designing culture systems to recapitulate the in vivo oxygen environment, it is important to integrate systems for monitoring and controlling oxygen concentration. Herein, we report the design and engineering of a system to remotely monitor and control oxygen concentration inside a device for 3D cell culture. We integrate a photonic oxygen biosensor into the 3D tissue scaffold and regulate oxygen concentration via the control of purging gas flow. The integrated phosphorescence-based oxygen biosensor employs the quenching of palladium-benzoporphyrin by molecular oxygen to transduce the local oxygen concentration in the 3D tissue scaffold. The system is validated by testing the effects of normoxic and hypoxic culture conditions on healthy and tumorigenic breast epithelial cells, MCF-10A cells and BT474 cells, respectively. Under hypoxic conditions, both cell types exhibited upregulation of downstream target genes for the hypoxia marker gene, hypoxia-inducible factor 1α (HIF1A). Lastly, by monitoring the real-time fluctuation of oxygen concentration, we illustrated the formation of hypoxic culture conditions due to limited diffusion of oxygen through 3D tissue scaffolds.
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Affiliation(s)
- Kristina R Rivera
- Joint Department of Biomedical Engineering, North Carolina State University and University of North Carolina at Chapel Hill, 911 Oval Dr., Raleigh, NC 27695, USA
| | - Vladimir A Pozdin
- Department of Electrical & Computer Engineering, North Carolina State University, 890 Oval Dr., Raleigh, NC 27695, USA
| | - Ashlyn T Young
- Joint Department of Biomedical Engineering, North Carolina State University and University of North Carolina at Chapel Hill, 911 Oval Dr., Raleigh, NC 27695, USA
| | - Patrick D Erb
- Joint Department of Biomedical Engineering, North Carolina State University and University of North Carolina at Chapel Hill, 911 Oval Dr., Raleigh, NC 27695, USA
| | | | - Scott T Magness
- Joint Department of Biomedical Engineering, North Carolina State University and University of North Carolina at Chapel Hill, 911 Oval Dr., Raleigh, NC 27695, USA; Department of Cell Biology & Physiology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA; Department of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Michael Daniele
- Joint Department of Biomedical Engineering, North Carolina State University and University of North Carolina at Chapel Hill, 911 Oval Dr., Raleigh, NC 27695, USA; Department of Electrical & Computer Engineering, North Carolina State University, 890 Oval Dr., Raleigh, NC 27695, USA.
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12
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Young AT, Cornwell N, Daniele MA. Neuro-Nano Interfaces: Utilizing Nano-Coatings and Nanoparticles to Enable Next-Generation Electrophysiological Recording, Neural Stimulation, and Biochemical Modulation. Adv Funct Mater 2018; 28:1700239. [PMID: 33867903 PMCID: PMC8049593 DOI: 10.1002/adfm.201700239] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
Neural interfaces provide a window into the workings of the nervous system-enabling both biosignal recording and modulation. Traditionally, neural interfaces have been restricted to implanted electrodes to record or modulate electrical activity of the nervous system. Although these electrode systems are both mechanically and operationally robust, they have limited utility due to the resultant macroscale damage from invasive implantation. For this reason, novel nanomaterials are being investigated to enable new strategies to chronically interact with the nervous system at both the cellular and network level. In this feature article, the use of nanomaterials to improve current electrophysiological interfaces, as well as enable new nano-interfaces to modulate neural activity via alternative mechanisms, such as remote transduction of electromagnetic fields are explored. Specifically, this article will review the current use of nanoparticle coatings to enhance electrode function, then an analysis of the cutting-edge, targeted nanoparticle technologies being utilized to interface with both the electrophysiological and biochemical behavior of the nervous system will be provided. Furthermore, an emerging, specialized-use case for neural interfaces will be presented: the modulation of the blood-brain barrier.
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Affiliation(s)
- Ashlyn T Young
- Joint Department of Biomedical Engineering, University of North Carolina at Chapel Hill, and North Carolina State University, 911 Oval Dr., Raleigh, NC 27695, USA
| | - Neil Cornwell
- Joint Department of Biomedical Engineering, University of North Carolina at Chapel Hill, and North Carolina State University, 911 Oval Dr., Raleigh, NC 27695, USA
| | - Michael A Daniele
- Joint Department of Biomedical Engineering, University of North Carolina at Chapel Hill, and North Carolina State University, 911 Oval Dr., Raleigh, NC 27695, USA
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13
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Scholl A, Marcus MA, Doran A, Nasiatka JR, Young AT, MacDowell AA, Streubel R, Kent N, Feng J, Wan W, Padmore HA. Hartmann characterization of the PEEM-3 aberration-corrected X-ray photoemission electron microscope. Ultramicroscopy 2018; 188:77-84. [PMID: 29554489 DOI: 10.1016/j.ultramic.2018.03.010] [Citation(s) in RCA: 4] [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: 12/06/2017] [Revised: 03/06/2018] [Accepted: 03/09/2018] [Indexed: 11/24/2022]
Abstract
Aberration correction by an electron mirror dramatically improves the spatial resolution and transmission of photoemission electron microscopes. We will review the performance of the recently installed aberration corrector of the X-ray Photoemission Electron Microscope PEEM-3 and show a large improvement in the efficiency of the electron optics. Hartmann testing is introduced as a quantitative method to measure the geometrical aberrations of a cathode lens electron microscope. We find that aberration correction leads to an order of magnitude reduction of the spherical aberrations, suggesting that a spatial resolution of below 100 nm is possible at 100% transmission of the optics when using x-rays. We demonstrate this improved performance by imaging test patterns employing element and magnetic contrast.
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Affiliation(s)
- A Scholl
- Advanced Light Source, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley CA 94720, USA.
| | - M A Marcus
- Advanced Light Source, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley CA 94720, USA
| | - A Doran
- Advanced Light Source, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley CA 94720, USA
| | - J R Nasiatka
- Advanced Light Source, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley CA 94720, USA
| | - A T Young
- Advanced Light Source, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley CA 94720, USA
| | - A A MacDowell
- Advanced Light Source, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley CA 94720, USA
| | - R Streubel
- Materials Sciences Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley CA 94720, USA
| | - N Kent
- Materials Sciences Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley CA 94720, USA; Department of Physics, University of California, Santa Cruz, Santa Cruz, CA 95064, USA
| | - J Feng
- Advanced Light Source, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley CA 94720, USA
| | - W Wan
- Advanced Light Source, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley CA 94720, USA
| | - H A Padmore
- Advanced Light Source, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley CA 94720, USA
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14
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Stover K, Fukuyama T, Young AT, Daniele MA, Oberley R, Crapo JD, Bäumer W. Topically applied manganese-porphyrins BMX-001 and BMX-010 display a significant anti-inflammatory response in a mouse model of allergic dermatitis. Arch Dermatol Res 2016; 308:711-721. [PMID: 27709295 DOI: 10.1007/s00403-016-1693-0] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2016] [Revised: 08/23/2016] [Accepted: 09/30/2016] [Indexed: 01/18/2023]
Abstract
In this study, we topically administered two antioxidant compounds, the manganese-porphyrin-derivatives BMX-001 and BMX-010, in a mouse model of allergic dermatitis and compared the efficacy for reduction of itch and inflammation. In vitro effects of BMX-001 and BMX-010 on keratinocytes, bone marrow derived dendritic cells (BMDCs) and T-cells were initially analysed. For assessment of scratching behaviour, BMX-001 and BMX-010 (0.01 and 0.1 %) were topically applied 16 h and/or 1 h before compound 48/80 or toluene-2,4,-diisocyanate (TDI) challenge in a TDI induced mouse dermatitis model. Additionally, assessment of allergic skin inflammation was performed in a similar manner in the TDI model. Post-treatment ear thickness was measured 24 h after TDI challenge and compared to basal values. The mice were sacrificed and the ear auricle was removed for further analysis. In vitro, both BMX substances significantly inhibited cytokine production of keratinocytes as well as of BMDC and T-cell proliferation. Topical treatment with BMX cream resulted in a significant decrease in scratching behaviour in the compound 48/80 model, but not in the TDI model. Mice treated with BMX-001 and BMX-010 showed a moderate dose dependent decrease in ear thickness, and interestingly, the concentration of the cytokines IL-1β and IL-4 in inflamed skin was reduced by 80-90 % by all treatment options. These first results suggest the potential benefit of a BMX-001 and BMX-010 cream for the treatment of allergic-inflammatory skin diseases.
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Affiliation(s)
- Kelsey Stover
- Department of Molecular Biomedical Sciences, College of Veterinary Medicine, North Carolina State University, 1060 William Moore Drive, Raleigh, NC, 27607, USA
| | - Tomoki Fukuyama
- Department of Molecular Biomedical Sciences, College of Veterinary Medicine, North Carolina State University, 1060 William Moore Drive, Raleigh, NC, 27607, USA
| | - Ashlyn T Young
- Joint Department of Biomedical Engineering, North Carolina State University and University of North Carolina, Chapel Hill, Chapel Hill, USA
| | - Michael A Daniele
- Joint Department of Biomedical Engineering, North Carolina State University and University of North Carolina, Chapel Hill, Chapel Hill, USA
| | - Rebecca Oberley
- BioMimetix JV, LLC, Englewood, CO, USA.,University of Nebraska Medical Center, Omaha, NE, USA
| | - James D Crapo
- BioMimetix JV, LLC, Englewood, CO, USA.,National Jewish Health, Denver, CO, USA
| | - Wolfgang Bäumer
- Department of Molecular Biomedical Sciences, College of Veterinary Medicine, North Carolina State University, 1060 William Moore Drive, Raleigh, NC, 27607, USA.
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15
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Gray AX, Jeong J, Aetukuri NP, Granitzka P, Chen Z, Kukreja R, Higley D, Chase T, Reid AH, Ohldag H, Marcus MA, Scholl A, Young AT, Doran A, Jenkins CA, Shafer P, Arenholz E, Samant MG, Parkin SSP, Dürr HA. Correlation-Driven Insulator-Metal Transition in Near-Ideal Vanadium Dioxide Films. Phys Rev Lett 2016; 116:116403. [PMID: 27035314 DOI: 10.1103/physrevlett.116.116403] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/06/2015] [Indexed: 06/05/2023]
Abstract
We use polarization- and temperature-dependent x-ray absorption spectroscopy, in combination with photoelectron microscopy, x-ray diffraction, and electronic transport measurements, to study the driving force behind the insulator-metal transition in VO_{2}. We show that both the collapse of the insulating gap and the concomitant change in crystal symmetry in homogeneously strained single-crystalline VO_{2} films are preceded by the purely electronic softening of Coulomb correlations within V-V singlet dimers. This process starts 7 K (±0.3 K) below the transition temperature, as conventionally defined by electronic transport and x-ray diffraction measurements, and sets the energy scale for driving the near-room-temperature insulator-metal transition in this technologically promising material.
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Affiliation(s)
- A X Gray
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA
- Department of Physics, Temple University, 1925 North 12th Street, Philadelphia, Pennsylvania 19130, USA
| | - J Jeong
- IBM Almaden Research Center, 650 Harry Road, San Jose, California 95120, USA
| | - N P Aetukuri
- IBM Almaden Research Center, 650 Harry Road, San Jose, California 95120, USA
| | - P Granitzka
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA
- Van der Waals-Zeeman Institute, University of Amsterdam, 1018XE Amsterdam, The Netherlands
| | - Z Chen
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA
- Department of Physics, Stanford University, Stanford, California 94305, USA
| | - R Kukreja
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA
- Department of Materials Science and Engineering, Stanford University, Stanford, California 94305, USA
| | - D Higley
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA
- Department of Applied Physics, Stanford University, Stanford, California 94305, USA
| | - T Chase
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA
- Department of Applied Physics, Stanford University, Stanford, California 94305, USA
| | - A H Reid
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA
| | - H Ohldag
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA
| | - M A Marcus
- Advanced Light Source, Lawrence Berkeley National Laboratory, One Cyclotron Road, Berkeley, California 94720, USA
| | - A Scholl
- Advanced Light Source, Lawrence Berkeley National Laboratory, One Cyclotron Road, Berkeley, California 94720, USA
| | - A T Young
- Advanced Light Source, Lawrence Berkeley National Laboratory, One Cyclotron Road, Berkeley, California 94720, USA
| | - A Doran
- Advanced Light Source, Lawrence Berkeley National Laboratory, One Cyclotron Road, Berkeley, California 94720, USA
| | - C A Jenkins
- Advanced Light Source, Lawrence Berkeley National Laboratory, One Cyclotron Road, Berkeley, California 94720, USA
| | - P Shafer
- Advanced Light Source, Lawrence Berkeley National Laboratory, One Cyclotron Road, Berkeley, California 94720, USA
| | - E Arenholz
- Advanced Light Source, Lawrence Berkeley National Laboratory, One Cyclotron Road, Berkeley, California 94720, USA
| | - M G Samant
- IBM Almaden Research Center, 650 Harry Road, San Jose, California 95120, USA
| | - S S P Parkin
- IBM Almaden Research Center, 650 Harry Road, San Jose, California 95120, USA
| | - H A Dürr
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA
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16
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Abstract
Neutrophils are critical inflammatory cells; thus, it is important to characterize the effects of drugs on neutrophil function in the context of inflammatory diseases. Herein, chemically guided neutrophil migration, known as chemotaxis, is studied in the context of drug treatment at the single cell level using a microfluidic platform, complemented by cell viability assays and calcium imaging. Three representative drugs known to inhibit surface receptor expression, signaling enzyme activity, and the elevation of intracellular Ca(2+) levels, each playing a significant role in neutrophil chemotactic pathways, are used to examine the in vitro drug effects on cellular behaviors. The microfluidic device establishes a stable concentration gradient of chemokines across a cell culture chamber so that neutrophil migration can be monitored under various drug-exposure conditions. Different time- and concentration-dependent regulatory effects were observed by comparing the motility, polarization, and effectiveness of neutrophil chemotaxis in response to the three drugs. Viability assays revealed distinct drug capabilities in reducing neutrophil viability while calcium imaging clarified the role of Ca(2+) in the neutrophil chemotaxis. This study provides mechanistic insight into the drug effects on neutrophil function, facilitating comparison of current and potential pharmaceutical approaches.
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Affiliation(s)
- Xiaojie Wu
- Department of Chemistry, University of Minnesota, 207 Pleasant Street SE, Minneapolis, Minnesota 55455, USA.
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17
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Abstract
![]()
The human body is a complex network of molecules,
organelles, cells,
tissues, and organs: an uncountable number of interactions and transformations
interconnect all the system’s components. In addition to these
biochemical components, biophysical components, such as pressure,
flow, and morphology, and the location of all of these interactions
play an important role in the human body. Technical difficulties have
frequently limited researchers from observing cellular biology as
it occurs within the human body, but some state-of-the-art analytical
techniques have revealed distinct cellular behaviors that occur only
in the context of the interactions. These types of findings have inspired
bioanalytical chemists to provide new tools to better understand these
cellular behaviors and interactions. What blocks us from understanding
critical biological interactions
in the human body? Conventional approaches are often too naïve
to provide realistic data and in vivo whole animal studies give complex
results that may or may not be relevant for humans. Microfluidics
offers an opportunity to bridge these two extremes: while these studies
will not model the complexity of the in vivo human system, they can
control the complexity so researchers can examine critical factors
of interest carefully and quantitatively. In addition, the use of
human cells, such as cells isolated from donated blood, captures human-relevant
data and limits the use of animals in research. In addition, researchers
can adapt these systems easily and cost-effectively to a variety of
high-end signal transduction mechanisms, facilitating high-throughput
studies that are also spatially, temporally, or chemically resolved.
These strengths should allow microfluidic platforms to reveal critical
parameters in the human body and provide insights that will help with
the translation of pharmacological advances to clinical trials. In this Account, we describe selected microfluidic innovations
within the last 5 years that focus on modeling both biophysical and
biochemical interactions in cellular communication, such as flow and
cell–cell networks. We also describe more advanced systems
that mimic higher level biological networks, such as organ on-a-chip
and animal on-a-chip models. Since the first papers in the early 1990s,
interest in the bioanalytical use of microfluidics has grown significantly.
Advances in micro-/nanofabrication technology have allowed researchers
to produce miniaturized, biocompatible assay platforms suitable for
microfluidic studies in biochemistry and chemical biology. Well-designed
microfluidic platforms can achieve quick, in vitro analyses on pico-
and femtoliter volume samples that are temporally, spatially, and
chemically resolved. In addition, controlled cell culture techniques
using a microfluidic platform have produced biomimetic systems that
allow researchers to replicate and monitor physiological interactions.
Pioneering work has successfully created cell–fluid, cell–cell,
cell–tissue, tissue–tissue, even organ-like level interfaces.
Researchers have monitored cellular behaviors in these biomimetic
microfluidic environments, producing validated model systems to understand
human pathophysiology and to support the development of new therapeutics.
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Affiliation(s)
- Donghyuk Kim
- Department of Chemistry, University of Minnesota, 207 Pleasant
Street Southeast, Minneapolis, Minnesota 55455, United States
| | - Xiaojie Wu
- Department of Chemistry, University of Minnesota, 207 Pleasant
Street Southeast, Minneapolis, Minnesota 55455, United States
| | - Ashlyn T. Young
- Department of Chemistry, University of Minnesota, 207 Pleasant
Street Southeast, Minneapolis, Minnesota 55455, United States
| | - Christy L. Haynes
- Department of Chemistry, University of Minnesota, 207 Pleasant
Street Southeast, Minneapolis, Minnesota 55455, United States
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18
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Burkhardt MH, Hossain MA, Sarkar S, Chuang YD, Cruz Gonzalez AG, Doran A, Scholl A, Young AT, Tahir N, Choi YJ, Cheong SW, Dürr HA, Stöhr J. Imaging the first-order magnetic transition in La0.35Pr0.275Ca0.375MnO3. Phys Rev Lett 2012; 108:237202. [PMID: 23003984 DOI: 10.1103/physrevlett.108.237202] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/21/2012] [Indexed: 05/23/2023]
Abstract
The nature of the ferromagnetic, charge, orbital, and antiferromagnetic order in La0.35Pr0.275Ca0.375MnO3 on the nano- and microscale was investigated by photoemission electron microscopy (PEEM) and resonant elastic soft x-ray scattering (RSXS). The structure of the ferromagnetic domains around the Curie temperature T(C) indicates that they nucleate under a high degree of lattice strain, which is brought about by the charge, orbital, and antiferromagnetic order. The combined temperature-dependent PEEM and RSXS measurements suggest that the lattice distortions associated with charge and orbital order are glassy in nature and that phase separation is driven by the interplay between it and the more itinerant charge carriers associated with ferromagnetic metallic order, even well below T(C).
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Affiliation(s)
- Mark H Burkhardt
- Stanford Institute for Materials and Energy Sciences (SIMES), SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
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19
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Gann E, Young AT, Collins BA, Yan H, Nasiatka J, Padmore HA, Ade H, Hexemer A, Wang C. Soft x-ray scattering facility at the Advanced Light Source with real-time data processing and analysis. Rev Sci Instrum 2012; 83:045110. [PMID: 22559579 DOI: 10.1063/1.3701831] [Citation(s) in RCA: 109] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
We present the development and characterization of a dedicated resonant soft x-ray scattering facility. Capable of operation over a wide energy range, the beamline and endstation are primarily used for scattering from soft matter systems around the carbon K-edge (∼285 eV). We describe the specialized design of the instrument and characteristics of the beamline. Operational characteristics of immediate interest to users such as polarization control, degree of higher harmonic spectral contamination, and detector noise are delineated. Of special interest is the development of a higher harmonic rejection system that improves the spectral purity of the x-ray beam. Special software and a user-friendly interface have been implemented to allow real-time data processing and preliminary data analysis simultaneous with data acquisition.
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Affiliation(s)
- E Gann
- Department of Physics, North Carolina State University, Raleigh, North Carolina 27695-8202, USA
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20
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Wang C, Hexemer A, Nasiatka J, Chan ER, Young AT, Padmore HA, Schlotter WF, Lüning J, Swaraj S, Watts B, Gann E, Yan H, Ade H. Resonant Soft X-ray Scattering of Polymers with a 2D Detector: Initial Results and System Developments at the Advanced Light Source. ACTA ACUST UNITED AC 2010. [DOI: 10.1088/1757-899x/14/1/012016] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [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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21
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Opachich YP, Comin A, Bartelt AF, Young AT, Scholl A, Feng J, Schmalhorst J, Shin HJ, Engelhorn K, Risbud SH, Reiss G, Padmore HA. Time-resolved demagnetization of Co2MnSi observed using x-ray magnetic circular dichroism and an ultrafast streak camera. J Phys Condens Matter 2010; 22:156003. [PMID: 21389561 DOI: 10.1088/0953-8984/22/15/156003] [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: 05/30/2023]
Abstract
The demagnetization dynamics of the Heusler alloy Co(2)MnSi was studied using picosecond time-resolved x-ray magnetic circular dichroism. The sample was excited using femtosecond laser pulses. In contrast to the sub-picosecond demagnetization of the metal ferromagnet Ni, substantially slower demagnetization with a time constant of 3.5 ± 0.5 ps was measured. This could be explained by a spin-dependent band gap inhibiting the spin-flip scattering of hot electrons in Co(2)MnSi, which is predicted to be half-metallic. A universal demagnetization time constant was measured across a range of pump power levels.
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Affiliation(s)
- Y P Opachich
- Lawrence Berkeley National Laboratory, Berkeley, CA 94720-8099, USA.
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22
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Ohldag H, Scholl A, Nolting F, Arenholz E, Maat S, Young AT, Carey M, Stöhr J. Correlation between exchange bias and pinned interfacial spins. Phys Rev Lett 2003; 91:017203. [PMID: 12906569 DOI: 10.1103/physrevlett.91.017203] [Citation(s) in RCA: 117] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/19/2002] [Indexed: 05/24/2023]
Abstract
Using x-ray magnetic circular dichroism, we have detected the very interfacial spins that are responsible for the horizontal loop shift in three different exchange bias sandwiches, chosen because of their potential for device applications. The "pinned" uncompensated interfacial spins constitute only a fraction of a monolayer and do not rotate in an external magnetic field since they are tightly locked to the antiferromagnetic lattice. A simple extension of the Meiklejohn and Bean model is proposed to account quantitatively for the exchange bias fields in the three studied systems from the experimentally determined number of pinned moments and their sizes.
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Affiliation(s)
- H Ohldag
- Stanford Synchrotron Radiation Laboratory, P.O. Box 20450, Stanford, California 94309, USA.
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23
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Lakey JR, Young AT, Pardue D, Calvin S, Albertson TE, Jacobson L, Cavanagh TJ. Nonviral transfection of intact pancreatic islets. Cell Transplant 2002; 10:697-708. [PMID: 11814112] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/23/2023] Open
Abstract
Ex vivo gene transfer offers a potential means to introduce genes into cells, which may play an important role in preventing graft rejection and inducing graft tolerance. This study examined the efficiency and toxicity of several lipid-based transfection reagents (LipofectAMINE, DOTAP, and DOSPER) in intact pancreatic islets. Isolated islets were transfected with a pCMV-beta-galactosidase plasmid using several DNA/liposome ratios (1:12) of liposomes (3-72 microl) and DNA (3 and 6 microg). Transfection efficiency was quantified by microscopic evaluation of beta-galactosidase gene expression in whole intact islets. Functionality of the transfected islets was measured by insulin response to glucose solutions. All transfection reagents evaluated in this study transfected cells within the islets. As expected, untransfected controls and transfected islets with DNA alone did not express beta-gal. The highest transfection efficiency and functional viability were obtained following a 48-h incubation after exposure to the transfection mixtures as follows: 3 microl DNA and 18 microl DOTAP/ml (1:6 ratio), 6 microg DNA and 12 microl DOSPER/ml (1:2 ratio), or 6 microg DNA and 12 microl Lipofect-AMINE/ml (1:2 ratio). The highest rate of transfected cells per islet was obtained using DOTAP. In vitro functionality was not significantly different between DOTAP and nontreated controls. However, optimal transfection efficiency doses of LipofectAMINE and DOSPER significantly reduced the stimulated insulin response of the transfected islets (p < 0.05, ANOVA). The calculated stimulation index (SI) was 7.8+/-0.6 (mean +/- SEM) for DOTAP-transfected islets compared with 8.4+/-0.5 for nontransfected control islets (p = ns). The SI of DOSPER- and LipofectAMINE-transfected islets was significantly lower (6.1+/-0.5 and 3.4+/-0.5, respectively, p < 0.05). Lipid-based transfection using DOTAP at a DNA/lipid ratio of 1:6 provides an effective means of ex vivo gene delivery without compromising in vitro functionality of the transfected islets.
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Affiliation(s)
- J R Lakey
- Department of Surgery, Surgical-Medical Research Institute, University of Alberta, Edmonton, Canada.
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Young AT, Arenholz E, Marks S, Schlueter R, Steier C, Padmore HA, Hitchcock AP, Castner DG. Variable linear polarization from an X-ray undulator. J Synchrotron Radiat 2002; 9:270-274. [PMID: 12091739 DOI: 10.1107/s0909049502007161] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/12/2001] [Accepted: 04/18/2002] [Indexed: 05/23/2023]
Abstract
A new X-ray undulator has been designed and constructed which produces linearly polarized X-rays in which the plane of polarization can be oriented to a user selectable angle, from horizontal to vertical. Based on the Apple-II elliptically polarizing undulator (EPU), the undulator rotates the angle of the linear polarization by a simple longitudinal motion of the undulator magnets. Combined with the circular and elliptical polarization capabilities of the EPU operating in the standard mode, this new undulator produces soft X-ray radiation with versatile polarization control. This paper describes the magnetic structure of the device and presents an analysis of the magnetic field with varying undulator parameters. The variable linear polarization capability is then exhibited by measuring the X-ray absorption spectrum of an oriented polytetrafluoroethylene thin film. This experiment, which measures the linear dichroism of the sample at two peaks near the C 1s absorption edge, demonstrates the continuous polarization rotation capabilities of the undulator.
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Affiliation(s)
- A T Young
- Advanced Light Source Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA.
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25
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Jahnke T, Weber T, Landers AL, Knapp A, Schössler S, Nickles J, Kammer S, Jagutzki O, Schmidt L, Czasch A, Osipov T, Arenholz E, Young AT, Díez Muiño R, Rolles D, García de Abajo FJ, Fadley CS, Van Hove MA, Semenov SK, Cherepkov NA, Rösch J, Prior MH, Schmidt-Böcking H, Cocke CL, Dörner R. Circular dichroism in K-shell ionization from fixed-in-space CO and N2 molecules. Phys Rev Lett 2002; 88:073002. [PMID: 11863892 DOI: 10.1103/physrevlett.88.073002] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/17/2001] [Indexed: 05/23/2023]
Abstract
We have measured the angular distributions of 1s photoelectrons excited by circularly and linearly polarized light from fixed-in-space CO and N2 molecules, in the vicinity of their shape resonances. A strong circular dichroism, i.e., a strong dependence on the sense of rotation of the polarization vector of the photons, is found for both molecules. State-of-the-art one-electron multiple scattering and partially correlated random phase approximation calculations are in good agreement with many, but not all, aspects of the experimental data.
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Affiliation(s)
- T Jahnke
- Institut für Kernphysik, University Frankfurt, August-Euler Strasse 6, D-60486 Frankfurt, Germany
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26
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Young AT. Mars/Viking 25th Anniversary Tribute. Viking redux: Viking success and lessons for the future. Astrobiology 2001; 1:501-504. [PMID: 12448984 DOI: 10.1089/153110701753593919] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Affiliation(s)
- A T Young
- Department of Geology, 1721 SW Broadway, 17 Cramer Hall, Portland State University, Portland, OR 97201, USA
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27
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Young AT. Sunset science. III. Visual adaptation and green flashes. J Opt Soc Am A Opt Image Sci Vis 2000; 17:2129-2139. [PMID: 11140471 DOI: 10.1364/josaa.17.002129] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Photographs of green flashes do not preclude a role for physiological effects in these phenomena. While green flashes are certainly not after-images, there is compelling evidence that adaptation in the visual system strongly affects the perceived color of most sunset green flashes. Furthermore, the retinal image of the setting Sun is usually bright enough to bleach most of the red-sensitive photopigment in a few seconds, making the yellow stage of a sunset flash appear green. Even in air so hazy that no green light reaches the eye, a yellow flash may occur and appear green. Many, but not all, visual observations of sunset green flashes are of this yellow flash. The yellow portion of sunset green flashes helps explain their reported durations, which exceed those expected for the appearance of green light alone.
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Affiliation(s)
- A T Young
- Department of Astronomy, San Diego State University, California 92182-1221, USA
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Abstract
A series of patients with single major scoliosis curvatures attributable to spina bifida treated by anterior only spinal fusion was studied for 2 years to determine whether the infection rate could be decreased, adequate correction and pelvic balance could be provided, and posterior surgery could be avoided in these patients. Anterior surgery alone was performed for thoracolumbar scoliosis greater than 45 degrees if the compensatory thoracic curve was less than 40 degrees and there was no significant junctional kyphosis. Fourteen patients were treated at a mean age of 11.9 years (range, 7-16 years), with a mean curve of 64 degrees (range, 51 degrees-85 degrees), and motor levels distributed from T10-L4. Thirteen patients had prior neurosurgery for tether, syrinx, or Arnold-Chiari malformation. The spine was fused over a mean of seven vertebrae. A 3/16 inch Texas Scottish Rite Hospital rod was used most commonly (10 patients). Blood loss averaged 1100 cc. The mean curve correction was 57% at 40 months after surgery. Loss of correction occurred primarily by adding on outside the instrumented area. Mean pelvic obliquity was improved from 16 degrees to 9 degrees. There was one superficial infection. Results were good in five patients, fair in four, and poor in five. Failures were attributable to proximal decompensation in two patients who required revision surgery (two), neurologic deterioration in two, and screw pullout in one. Both patients with decompensation had syringomyelia. Both patients with neurologic deterioration had large curves (> 75 degrees). Both patients recovered after rod removal. Retrospectively, by eliminating patients with syrinx or with a curve greater than 75 degrees, all poor results would be eliminated. Anterior only fusion and instrumentation may have significant advantages, but only for selected patients with thoracolumbar curves less than 75 degrees, compensatory curves less than 40 degrees, no increased kyphosis, and no syrinx. Quadriceps function should be monitored. On the basis of this preliminary experience, continued use of this approach using stricter selection seems warranted.
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Affiliation(s)
- P D Sponseller
- Department of Orthopaedics, Johns Hopkins University, Baltimore, MD, USA
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Abstract
We present diagrams that show how layers in atmospheric thermal structure are related to the altitudes at which they are seen tangentially. These dip diagrams show that the inferior mirage greatly magnifies the apparent angular size of the lowest few centimeters of atmosphere. Conversely, inversion layers below eye level are compressed-even to zero apparent thickness, in ducts. The diagrams show that, even when distant objects are miraged, the ray crossings occur beyond the lowest point on each ray where the line of sight is tangent to a horizontal surface in the atmosphere. Therefore the apparent altitudes of these tangent points are a monotonic function of their actual heights in the atmosphere. This monotonicity explains an apparent paradox in low-Sun images.
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Abstract
A previously unrecognized phenomenon, which we call the mock mirage, produces inverted images of the Sun and Moon near the horizon when the observer looks downward through a thermal inversion. No ducting is involved; the rays can be concave toward the Earth throughout their length, with a radius of curvature larger than the radius of the Earth. Quite mild inversions produce surprisingly large effects, which increase with the height of the observer. Although the phenomenon has frequently been photographed, published pictures have been misinterpreted. Finally, we distinguish between features that are due to waves on inversion layers and the larger features that are due to the inversions themselves.
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Young AT, Dahl J, Hausdorff SF, Bauer PH, Birnbaum MJ, Benjamin TL. Phosphatidylinositol 3-kinase binding to polyoma virus middle tumor antigen mediates elevation of glucose transport by increasing translocation of the GLUT1 transporter. Proc Natl Acad Sci U S A 1995; 92:11613-7. [PMID: 8524814 PMCID: PMC40452 DOI: 10.1073/pnas.92.25.11613] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Elevation in the rate of glucose transport in polyoma virus-infected mouse fibroblasts was dependent upon phosphatidylinositol 3-kinase (PI 3-kinase; EC 2.7.1.137) binding to complexes of middle tumor antigen (middle T) and pp60c-src. Wild-type polyoma virus infection led to a 3-fold increase in the rate of 2-deoxyglucose (2DG) uptake, whereas a weakly transforming polyoma virus mutant that encodes a middle T capable of activating pp60c-src but unable to promote binding of PI 3-kinase induced little or no change in the rate of 2DG transport. Another transformation-defective mutant encoding a middle T that retains functional binding of both pp60c-src and PI 3-kinase but is incapable of binding Shc (a protein involved in activation of Ras) induced 2DG transport to wild-type levels. Wortmannin (< or = 100 nM), a known inhibitor of PI 3-kinase, blocked elevation of glucose transport in wild-type virus-infected cells. In contrast to serum stimulation, which led to increased levels of glucose transporter 1 (GLUT1) RNA and protein, wild-type virus infection induced no significant change in levels of either GLUT1 RNA or protein. Nevertheless, virus-infected cells did show increases in GLUT1 protein in plasma membranes. These results point to a posttranslational mechanism in the elevation of glucose transport by polyoma virus middle T involving activation of PI 3-kinase and translocation of GLUT1.
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Affiliation(s)
- A T Young
- Department of Pathology, Harvard Medical School, Boston, MA 02115, USA
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32
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Abstract
Approximate formulas are presented for relative optical air mass as a function of true, rather than refracted, zenith angle.
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Rehr H, Blumenfield S, Young AT, Rosenberg G. Social work accountability: a key to high-quality patient care and services. Mt Sinai J Med 1993; 60:368-73. [PMID: 8259115] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Affiliation(s)
- H Rehr
- Department of Social Work Services, Mount Sinai Medical Center, New York, NY 10029
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34
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Abstract
We correct an error in a widely used air mass table by recalculating the values on the basis of the ISO Standard Atmosphere (1972) and revise its approximation formula.
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35
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Talmage DA, Freund R, Young AT, Dahl J, Dawe CJ, Benjamin TL. Phosphorylation of middle T by pp60c-src: a switch for binding of phosphatidylinositol 3-kinase and optimal tumorigenesis. Cell 1989; 59:55-65. [PMID: 2551507 DOI: 10.1016/0092-8674(89)90869-6] [Citation(s) in RCA: 148] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Substitution of phenylalanine for tyrosine 315 of the polyoma virus middle T (mT) protein lowers the incidence and limits the spectrum of tumors induced following inoculation of the virus into newborn mice. This substitution removes the major site of phosphorylation by pp60c-src without altering the ability of mT to associate with or to activate pp60c-src. The mutant mT fails to show binding of a phosphatidylinositol 3-kinase (Ptdlns 3-kinase) activity that is normally present in wild-type mT complexes. Furthermore, an anti-peptide antiserum that specifically recognizes mT lacking phosphate at tyrosine 315 precipitates binary (mT-pp60c-src) but not ternary (mT-pp60c-src-Ptdlns 3-kinase) complexes from wild-type infected cell extracts. Reprecipitation with either anti-pp60c-src or anti-mT serum brings down ternary complexes containing mT phosphorylated on tyrosine 315. Phosphorylation of mT by pp60c-src in vivo is therefore a critical event for binding of Ptdlns 3-kinase and for expression of the full tumorigenic potential of the virus.
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Affiliation(s)
- D A Talmage
- Department of Pathology, Harvard Medical School, Boston, Massachusetts 02115
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Lips DL, Majerus PW, Gorga FR, Young AT, Benjamin TL. Phosphatidylinositol 3-phosphate is present in normal and transformed fibroblasts and is resistant to hydrolysis by bovine brain phospholipase C II. J Biol Chem 1989; 264:8759-63. [PMID: 2542286] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
The transforming protein of polyoma virus, middle T antigen, associates with two cellular enzymes, pp60c-src, a protein tyrosine kinase, and a phosphatidylinositol kinase that forms phosphatidylinositol 3-phosphate. The formation of a ternary complex of these proteins is essential for complete transformation and maximal tumor induction by the virus. A mutant virus encoding an altered middle T protein that activates pp60c-src but fails to bind phosphatidylinositol kinase is partially defective in transformation. We have confirmed, using an enzymological method, that the product of the in vitro reaction catalyzed by middle T-pp60c-src-phosphatidylinositol kinase complexes is phosphatidylinositol 3-phosphate (PtdIns(3)P), as previously reported (Whitman, M., Downes, C. P., Keeler, M., Keller, T., and Cantley, L. (1988) Nature 332, 644-646). PtdIns(3)P is present in normal as well as virus-infected and transformed cells at levels ranging from 0.6 to 2.6% of the major phosphatidylinositol phosphate isomer, phosphatidylinositol 4-phosphate (PtdIns(4)P). Steady-state levels of PtdIns(3)P do not appear to be affected by the expression of middle T in cells. PtdIns(3)P is not hydrolyzed by bovine brain phospholipase C II, which readily cleaves PtdIns(4)P and other phosphatidylinositols. This result underscores the likelihood that the metabolism of PtdIns(3)P is distinct from that of PtdIns(4)P and raises further questions regarding a possible role of PtdIns(3)P in normal and neoplastic cell growth.
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Affiliation(s)
- D L Lips
- Department of Internal Medicine, Washington University School of Medicine, St. Louis, Missouri 63110
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Lips DL, Majerus PW, Gorga FR, Young AT, Benjamin TL. Phosphatidylinositol 3-Phosphate Is Present in Normal and Transformed Fibroblasts and Is Resistant to Hydrolysis by Bovine Brain Phospholipase C II. J Biol Chem 1989. [DOI: 10.1016/s0021-9258(18)81858-0] [Citation(s) in RCA: 100] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
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Abstract
The present biosphere is shielded from harmful solar near ultraviolet (UV) radiation by atmospheric ozone. We suggest here that elemental sulfur vapor could have played a similar role in an anoxic, ozone-free, primitive atmosphere. Sulfur vapor would have been produced photochemically from volcanogenic SO2 and H2S. It is composed of ring molecules, primarily S8, that absorb strongly throughout the near UV, yet are expected to be relatively stable against photolysis and chemical attack. It is also insoluble in water and would thus have been immune to rainout or surface deposition over the oceans. The concentration of S8 in the primitive atmosphere would have been limited by its saturation vapor pressure, which is a strong function of temperature. Hence, it would have depended on the magnitude of the atmospheric greenhouse effect. Surface temperatures of 45 degrees C or higher, corresponding to carbon dioxide partial pressures exceeding 2 bars, are required to sustain an effective UV screen. Two additional requirements are that the ocean was saturated with sulfite and bisulfite, and that linear S8 chains must tend to reform rings faster than they are destroyed by photolysis. A warm, sulfur-rich, primitive atmosphere is consistent with inferences drawn from molecular phylogeny, which suggest that some of the earliest organisms were thermophilic bacteria that metabolized elemental sulfur.
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Affiliation(s)
- J F Kasting
- Space Science Division, NASA Ames Research Center, Moffett Field, CA 94035
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Cardella JF, Young AT, Smith TP, Darcy MD, Hunter DW, Castaneda-Zuniga WR, Knighton D, Nelson D, Amplatz K. Lower-extremity venous thrombosis: comparison of venography, impedance plethysmography, and intravenous manometry. Radiology 1988; 168:109-12. [PMID: 3380949 DOI: 10.1148/radiology.168.1.3380949] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
This study was undertaken to compare impedance plethysmography with lower-extremity venography and venous manometry in the diagnosis of acute deep venous thrombosis (DVT) of the lower extremity. Ninety-six extremities were studied. In this population, in which the prevalence of acute DVT was 43.8%, plethysmography had a sensitivity of 86.8% and a specificity of 72.0%. The predictive value of abnormal findings at plethysmography was 70.2%, and the predictive value of normal findings at plethysmography was 87.8%. Venous manometry was performed successfully in 89 extremities. A statistically significant difference was shown in the mean intravenous pressure between patients with and without acute DVT. However, there was considerable overlap between the two populations, limiting the predictive value of impedance plethysmography in any given patient.
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Affiliation(s)
- J F Cardella
- Department of Diagnostic Radiology, University of Minnesota Hospital and Clinic, Minneapolis
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40
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Abstract
We report a case of a recurrent perirenal cyst after 4 previous attempts to obliterate the cyst by more conventional means percutaneously and by open surgery. Endocystolysis, a technique for the internal marsupialization of a cyst into the renal collecting system, was used successfully to obliterate the cyst. This case and the technique of endocystolysis are described in detail.
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Affiliation(s)
- J C Hulbert
- Department of Urologic Surgery, University of Minnesota Hospital and Clinic, Minneapolis
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Smith TP, Young AT, Hunter DW, Darcy MD, Castaneda-Zuniga W, Amplatz K. Limited usefulness of carbon dioxide as a contrast agent for cholangiography. Gastrointest Radiol 1987; 12:43-4. [PMID: 3098619 DOI: 10.1007/bf01885101] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Carbon dioxide (CO2) was unsuccessfully used as a biliary contrast agent in 9 of 10 patients undergoing percutaneous transhepatic cholangiography prior to biliary drainage. The technique involved hand injection of 10-20 cc CO2 through the Chiba needle in an attempt to fill preferentially the anterior biliary radicals. Although CO2 remains a useful agent in many instances, particularly for percutaneous nephrostomy, its usefulness in the biliary tract is severely limited.
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Young AT. Discharge planning and ethical dilemmas. Disch Plann Update 1987; 7:3-4. [PMID: 10284842] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/12/2023]
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McKinstry CS, Steiner RE, Young AT, Jones L, Swirsky D, Aber V. Bone marrow in leukemia and aplastic anemia: MR imaging before, during, and after treatment. Radiology 1987; 162:701-7. [PMID: 3544034 DOI: 10.1148/radiology.162.3.3544034] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Serial magnetic resonance (MR) studies of the cervical bone marrow were performed in five patients undergoing bone marrow transplantation for chronic granulocytic leukemia and in four patients with aplastic anemia who were treated with antilymphocytic globulin. Findings were compared with those from a group of healthy volunteers. Chemical shift imaging techniques were used to exploit the presence of protons in fat and water in the red marrow. Characteristic changes were seen in aplastic anemia before treatment, but derivation of images representing fat and water fractions was necessary to distinguish leukemic marrow. Acute changes during the treatment of leukemia may reflect the effects of chemotherapy and radiation therapy, whereas changes in the chronic phase of both diseases may prove useful in predicting treatment outcome. MR studies are likely to be useful in the assessment and treatment of hematologic disorders.
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Hunter DW, Lund G, Rysavy JA, Castaneda-Zuniga W, Cardella JF, Young AT, Vladover Z, Amplatz K. Retrieving the Amplatz retrievable vena cava filter. Cardiovasc Intervent Radiol 1987; 10:32-6. [PMID: 3102067 DOI: 10.1007/bf02583304] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
The new Amplatz retrievable filter was placed 15 times into the inferior vena cava (IVC) of 7 dogs. Retrieval of the filter was attempted in 11 cases after 1 week and in 3 cases after 2 weeks. The retrieval was successful and without complication in all 14 cases. The 15th placement resulted in thrombotic occlusion of the IVC, and no retrieval was attempted.
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Young AT. NMR: principles, applications and recent advances. Australas Radiol 1986; 30:268-80. [PMID: 3814000 DOI: 10.1111/j.1440-1673.1986.tb01752.x] [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] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
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Young AT, Morin RL, Hunter DW, Nelson KL, Cardella JF, Castaneda-Zuniga WR, Amplatz K. Surface shield: device to reduce personnel radiation exposure. Radiology 1986; 159:801-3. [PMID: 3704160 DOI: 10.1148/radiology.159.3.3704160] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
A simple device is described that can reduce personnel exposure from scatter radiation by up to 75%. The device consists of an oblong piece of shielding (0.75-mm lead equivalent) that is taped to the side of the patient during percutaneous renal stone removal and other interventional procedures. Contrary to other shields and barriers, this does not interfere with access to the patient. Scatter exposure data from phantom studies are presented and the rationale for surface shielding discussed.
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Gehrtz M, Lenth W, Young AT, Johnston HS. High-frequency-modulation spectroscopy with a lead-salt diode laser. Opt Lett 1986; 11:132. [PMID: 19730556 DOI: 10.1364/ol.11.000132] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
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Mercado S, Hunter DW, Castaneda-Zuniga WR, Amplatz K, Young AT, Cardella JF, Lange PH, Hulbert JC, Reddy P. The double puncture: an effective percutaneous technique for removing complex, multiple renal calculi. Radiology 1986; 158:207-9. [PMID: 3940382 DOI: 10.1148/radiology.158.1.3940382] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Percutaneous nephrostolithotomy, which can require a double puncture, is presently the method of choice in our institution for the removal of renal stones. Patients that underwent this procedure were evaluated to identify the possible reasons for the double puncture. Of 200 patients evaluated, 14 needed a second tract. The three variables that determined whether a second puncture was needed, in order of importance, were number and size of the stones, with second tracts needed in patients with multiple stones and staghorn calculi; anatomical variations of the renal collecting system itself, with bifid systems the most significant anatomic variation; and the dexterity of the radiologist in performing the puncture and the ability of the urologist to extract the stone. Second tracts were needed more frequently in patients who presented with stones in both the lower and middle poles of the collecting systems.
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Young AT, Hulbert JC, Cardella JF, Hunter DW, Castaneda-Zuniga WR, Reddy P, Amplatz K. Percutaneous nephrostolithotomy: application to staghorn calculi. AJR Am J Roentgenol 1985; 145:1265-9. [PMID: 3877434 DOI: 10.2214/ajr.145.6.1265] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Twenty-five renal staghorn stones measuring at least 5 cm in diameter were removed percutaneously from 24 patients. Twelve patients required multiple access tracts for complete stone removal. Estimated blood loss more than 1000 ml occurred in 16 patients and temperature greater than 38.5 degrees C in 19 patients. All stones were successfully removed, with only two patients having definite residual fragments. Percutaneous nephrostolithotomy may be successfully applied to large staghorn stones. The relative roles of percutaneous therapy and extracorporeal lithotripsy remain to be determined.
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Abstract
In cases in which the ureters or biliary tree is encased by large tumors, it may be difficult to dilate a pathway for a stent with a balloon catheter. In ten consecutive patients in whom balloon dilatation was unsuccessful, a coaxial tapered Teflon cancer dilator successfully crossed the obstruction.
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