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Ray GS, Streeter SS, Bateman LM, Elliott JT, Henderson ER. Real-time identification of life-threatening necrotizing soft-tissue infections using indocyanine green fluorescence imaging. J Biomed Opt 2024; 29:066003. [PMID: 38745983 PMCID: PMC11092151 DOI: 10.1117/1.jbo.29.6.066003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/23/2024] [Revised: 04/02/2024] [Accepted: 04/25/2024] [Indexed: 05/16/2024]
Abstract
Significance Necrotizing soft-tissue infections (NSTIs) are life-threatening infections with a cumulative case fatality rate of 21%. The initial presentation of an NSTI is non-specific, frequently leading to misdiagnosis and delays in care. No current strategies yield an accurate, real-time diagnosis of an NSTI. Aim A first-in-kind, observational, clinical pilot study tested the hypothesis that measurable fluorescence signal voids occur in NSTI-affected tissues following intravenous administration and imaging of perfusion-based indocyanine green (ICG) fluorescence. This hypothesis is based on the established knowledge that NSTI is associated with local microvascular thrombosis. Approach Adult patients presenting to the Emergency Department of a tertiary care medical center at high risk for NSTI were prospectively enrolled and imaged with a commercial fluorescence imager. Single-frame fluorescence snapshot and first-pass perfusion kinetic parameters-ingress slope (IS), time-to-peak (TTP) intensity, and maximum fluorescence intensity (IMAX)-were quantified using a dynamic contrast-enhanced fluorescence imaging technique. Clinical variables (comorbidities, blood laboratory values), fluorescence parameters, and fluorescence signal-to-background ratios (SBRs) were compared to final infection diagnosis. Results Fourteen patients were enrolled and imaged (six NSTI, six cellulitis, one diabetes mellitus-associated gangrene, and one osteomyelitis). Clinical variables demonstrated no statistically significant differences between NSTI and non-NSTI patient groups (p -value ≥ 0.22 ). All NSTI cases exhibited prominent fluorescence signal voids in affected tissues, including tissue features not visible to the naked eye. All cellulitis cases exhibited a hyperemic response with increased fluorescence and no distinct signal voids. Median lesion-to-background tissue SBRs based on snapshot, IS, TTP, and IMAX parameter maps ranged from 3.2 to 9.1, 2.2 to 33.8, 1.0 to 7.5, and 1.5 to 12.7, respectively, for the NSTI patient group. All fluorescence parameters except TTP demonstrated statistically significant differences between NSTI and cellulitis patient groups (p -value < 0.05 ). Conclusions Real-time, accurate discrimination of NSTIs compared with non-necrotizing infections may be possible with perfusion-based ICG fluorescence imaging.
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Affiliation(s)
- Gabrielle S. Ray
- Dartmouth Health, Department of Orthopaedics, Lebanon, New Hampshire, United States
- Dartmouth College, Geisel School of Medicine, Hanover, New Hampshire, United States
| | - Samuel S. Streeter
- Dartmouth Health, Department of Orthopaedics, Lebanon, New Hampshire, United States
- Dartmouth College, Geisel School of Medicine, Hanover, New Hampshire, United States
| | - Logan M. Bateman
- Dartmouth College, Thayer School of Engineering, Hanover, New Hampshire, United States
| | - Jonathan Thomas Elliott
- Dartmouth Health, Department of Orthopaedics, Lebanon, New Hampshire, United States
- Dartmouth College, Geisel School of Medicine, Hanover, New Hampshire, United States
- Dartmouth College, Thayer School of Engineering, Hanover, New Hampshire, United States
| | - Eric R. Henderson
- Dartmouth Health, Department of Orthopaedics, Lebanon, New Hampshire, United States
- Dartmouth College, Geisel School of Medicine, Hanover, New Hampshire, United States
- Dartmouth College, Thayer School of Engineering, Hanover, New Hampshire, United States
| | - NEFARIOUS Study Group
- Dartmouth Health, Department of Orthopaedics, Lebanon, New Hampshire, United States
- Dartmouth College, Geisel School of Medicine, Hanover, New Hampshire, United States
- Dartmouth College, Thayer School of Engineering, Hanover, New Hampshire, United States
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2
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Murphy EK, Bertsch SR, Klein SB, Rashedi N, Sun Y, Joyner MJ, Curry TB, Johnson CP, Regimbal RJ, Wiggins CC, Senefeld JW, Shepherd JRA, Elliott JT, Halter RJ, Vaze VS, Paradis NA. Non-invasive biomarkers for detecting progression toward hypovolemic cardiovascular instability in a lower body negative pressure model. Sci Rep 2024; 14:8719. [PMID: 38622207 PMCID: PMC11018605 DOI: 10.1038/s41598-024-59139-8] [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: 11/10/2023] [Accepted: 04/08/2024] [Indexed: 04/17/2024] Open
Abstract
Occult hemorrhages after trauma can be present insidiously, and if not detected early enough can result in patient death. This study evaluated a hemorrhage model on 18 human subjects, comparing the performance of traditional vital signs to multiple off-the-shelf non-invasive biomarkers. A validated lower body negative pressure (LBNP) model was used to induce progression towards hypovolemic cardiovascular instability. Traditional vital signs included mean arterial pressure (MAP), electrocardiography (ECG), plethysmography (Pleth), and the test systems utilized electrical impedance via commercial electrical impedance tomography (EIT) and multifrequency electrical impedance spectroscopy (EIS) devices. Absolute and relative metrics were used to evaluate the performance in addition to machine learning-based modeling. Relative EIT-based metrics measured on the thorax outperformed vital sign metrics (MAP, ECG, and Pleth) achieving an area-under-the-curve (AUC) of 0.99 (CI 0.95-1.00, 100% sensitivity, 87.5% specificity) at the smallest LBNP change (0-15 mmHg). The best vital sign metric (MAP) at this LBNP change yielded an AUC of 0.6 (CI 0.38-0.79, 100% sensitivity, 25% specificity). Out-of-sample predictive performance from machine learning models were strong, especially when combining signals from multiple technologies simultaneously. EIT, alone or in machine learning-based combination, appears promising as a technology for early detection of progression toward hemodynamic instability.
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Affiliation(s)
- Ethan K Murphy
- Thayer School of Engineering, Dartmouth College, Hanover, NH, 03755, USA.
| | - Spencer R Bertsch
- Thayer School of Engineering, Dartmouth College, Hanover, NH, 03755, USA
| | - Samuel B Klein
- Geisel School of Medicine, Dartmouth College, Hanover, NH, 03755, USA
- Dartmouth-Hitchcock Medical Center, Lebanon, NH, 03756, USA
| | - Navid Rashedi
- Thayer School of Engineering, Dartmouth College, Hanover, NH, 03755, USA
| | - Yifei Sun
- Thayer School of Engineering, Dartmouth College, Hanover, NH, 03755, USA
| | - Michael J Joyner
- Department of Anesthesiology and Perioperative Medicine, Mayo Clinic, Rochester, MN, 55902, USA
| | - Timothy B Curry
- Department of Anesthesiology and Perioperative Medicine, Mayo Clinic, Rochester, MN, 55902, USA
| | - Christopher P Johnson
- Department of Anesthesiology and Perioperative Medicine, Mayo Clinic, Rochester, MN, 55902, USA
| | - Riley J Regimbal
- Department of Anesthesiology and Perioperative Medicine, Mayo Clinic, Rochester, MN, 55902, USA
| | - Chad C Wiggins
- Department of Anesthesiology and Perioperative Medicine, Mayo Clinic, Rochester, MN, 55902, USA
| | - Jonathon W Senefeld
- Department of Anesthesiology and Perioperative Medicine, Mayo Clinic, Rochester, MN, 55902, USA
| | - John R A Shepherd
- Department of Anesthesiology and Perioperative Medicine, Mayo Clinic, Rochester, MN, 55902, USA
| | - Jonathan Thomas Elliott
- Thayer School of Engineering, Dartmouth College, Hanover, NH, 03755, USA
- Geisel School of Medicine, Dartmouth College, Hanover, NH, 03755, USA
- Dartmouth-Hitchcock Medical Center, Lebanon, NH, 03756, USA
| | - Ryan J Halter
- Thayer School of Engineering, Dartmouth College, Hanover, NH, 03755, USA
- Geisel School of Medicine, Dartmouth College, Hanover, NH, 03755, USA
| | - Vikrant S Vaze
- Thayer School of Engineering, Dartmouth College, Hanover, NH, 03755, USA
| | - Norman A Paradis
- Geisel School of Medicine, Dartmouth College, Hanover, NH, 03755, USA
- Dartmouth-Hitchcock Medical Center, Lebanon, NH, 03756, USA
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3
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Demidov VV, Clark MA, Streeter SS, Sottosanti JS, Gitajn IL, Elliott JT. High-energy open-fracture model with initial experience of fluorescence-guided bone perfusion assessment. J Orthop Res 2023; 41:1040-1048. [PMID: 36192829 PMCID: PMC10067537 DOI: 10.1002/jor.25443] [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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/23/2022] [Accepted: 09/12/2022] [Indexed: 02/04/2023]
Abstract
High-energy orthopedic injuries cause severe damage to soft tissues and are prone to infection and healing complications, making them a challenge to manage. Further research is facilitated by a clinically relevant animal model with commensurate fracture severity and soft-tissue damage, allowing evaluation of novel treatment options and techniques. Here we report a reproducible, robust, and clinically relevant animal model of high-energy trauma with extensive soft-tissue damage, based on compressed air-driven membrane rupture as the blast wave source. As proof-of-principle showing the reproducibility of the injury, we evaluate changes in tissue and bone perfusion for a range of different tibia fracture severities, using dynamic contrast-enhanced fluorescence imaging and microcomputed tomography. We demonstrate that fluorescence tracer temporal profiles for skin, femoral vein, fractured bone, and paw reflect the increasing impact of more powerful blasts causing a range of Gustilo grade I-III injuries. The maximum fluorescence intensity of distal tibial bone following 0.1 mg/kg intravenous indocyanine green injection decreased by 35% (p < 0.01), 75% (p < 0.001), and 87% (p < 0.001), following grade I, II, and III injuries, respectively, compared to uninjured bone. Other kinetic parameters of bone and soft tissue perfusion extracted from series of fluorescence images for each animal also showed an association with severity of trauma. In addition, the time-intensity profile of fluorescence showed marked differences in wash-in and wash-out patterns for different injury severities and anatomical locations. This reliable and realistic high-energy trauma model opens new research avenues to better understand infection and treatment strategies. Level of evidence: Level III; Case-control.
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Affiliation(s)
- Valentin V. Demidov
- Department of Orthopaedics, Dartmouth-Hitchcock Medical Centre, Lebanon, NH
- Geisel School of Medicine, Dartmouth College, Hanover, NH
| | - Megan A. Clark
- Thayer School of Engineering, Dartmouth College, Hanover, NH
| | | | | | - I. Leah Gitajn
- Department of Orthopaedics, Dartmouth-Hitchcock Medical Centre, Lebanon, NH
| | - Jonathan Thomas Elliott
- Department of Orthopaedics, Dartmouth-Hitchcock Medical Centre, Lebanon, NH
- Geisel School of Medicine, Dartmouth College, Hanover, NH
- Thayer School of Engineering, Dartmouth College, Hanover, NH
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4
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Streeter SS, Hebert KA, Bateman LM, Ray GS, Dean RE, Geffken KT, Resnick CT, Austin DC, Bell JE, Sparks MB, Gibbs SL, Samkoe KS, Gitajn IL, Elliott JT, Henderson ER. Current and Future Applications of Fluorescence Guidance in Orthopaedic Surgery. Mol Imaging Biol 2023; 25:46-57. [PMID: 36447084 PMCID: PMC10106269 DOI: 10.1007/s11307-022-01789-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2022] [Revised: 11/01/2022] [Accepted: 11/16/2022] [Indexed: 12/03/2022]
Abstract
Fluorescence-guided surgery (FGS) is an evolving field that seeks to identify important anatomic structures or physiologic phenomena with helpful relevance to the execution of surgical procedures. Fluorescence labeling occurs generally via the administration of fluorescent reporters that may be molecularly targeted, enzyme-activated, or untargeted, vascular probes. Fluorescence guidance has substantially changed care strategies in numerous surgical fields; however, investigation and adoption in orthopaedic surgery have lagged. FGS shows the potential for improving patient care in orthopaedics via several applications including disease diagnosis, perfusion-based tissue healing capacity assessment, infection/tumor eradication, and anatomic structure identification. This review highlights current and future applications of fluorescence guidance in orthopaedics and identifies key challenges to translation and potential solutions.
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Affiliation(s)
- Samuel S Streeter
- Thayer School of Engineering, Dartmouth College, Hanover, NH, 03755, USA.
| | - Kendra A Hebert
- Thayer School of Engineering, Dartmouth College, Hanover, NH, 03755, USA
| | - Logan M Bateman
- Thayer School of Engineering, Dartmouth College, Hanover, NH, 03755, USA.,Department of Orthopaedics, Dartmouth Health, Lebanon, NH, 03756, USA
| | - Gabrielle S Ray
- Department of Orthopaedics, Dartmouth Health, Lebanon, NH, 03756, USA.,Geisel School of Medicine, Dartmouth College, Hanover, NH, 03755, USA
| | - Ryan E Dean
- Department of Orthopaedics, Dartmouth Health, Lebanon, NH, 03756, USA.,Geisel School of Medicine, Dartmouth College, Hanover, NH, 03755, USA
| | - Kurt T Geffken
- Department of Orthopaedics, Dartmouth Health, Lebanon, NH, 03756, USA.,Geisel School of Medicine, Dartmouth College, Hanover, NH, 03755, USA
| | - Corey T Resnick
- Department of Orthopaedics, Dartmouth Health, Lebanon, NH, 03756, USA.,Geisel School of Medicine, Dartmouth College, Hanover, NH, 03755, USA
| | - Daniel C Austin
- Department of Orthopaedics, Dartmouth Health, Lebanon, NH, 03756, USA.,Geisel School of Medicine, Dartmouth College, Hanover, NH, 03755, USA
| | - John-Erik Bell
- Department of Orthopaedics, Dartmouth Health, Lebanon, NH, 03756, USA.,Geisel School of Medicine, Dartmouth College, Hanover, NH, 03755, USA
| | - Michael B Sparks
- Department of Orthopaedics, Dartmouth Health, Lebanon, NH, 03756, USA.,Geisel School of Medicine, Dartmouth College, Hanover, NH, 03755, USA
| | - Summer L Gibbs
- Oregon Health & Science University, Portland, OR, 97239, USA
| | - Kimberley S Samkoe
- Thayer School of Engineering, Dartmouth College, Hanover, NH, 03755, USA
| | - I Leah Gitajn
- Department of Orthopaedics, Dartmouth Health, Lebanon, NH, 03756, USA.,Geisel School of Medicine, Dartmouth College, Hanover, NH, 03755, USA
| | - Jonathan Thomas Elliott
- Thayer School of Engineering, Dartmouth College, Hanover, NH, 03755, USA.,Department of Orthopaedics, Dartmouth Health, Lebanon, NH, 03756, USA.,Geisel School of Medicine, Dartmouth College, Hanover, NH, 03755, USA.,Dartmouth Cancer Center, Dartmouth Health, Lebanon, NH, 03756, USA
| | - Eric R Henderson
- Thayer School of Engineering, Dartmouth College, Hanover, NH, 03755, USA.,Department of Orthopaedics, Dartmouth Health, Lebanon, NH, 03756, USA.,Geisel School of Medicine, Dartmouth College, Hanover, NH, 03755, USA.,Dartmouth Cancer Center, Dartmouth Health, Lebanon, NH, 03756, USA
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5
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Streeter SS, Ray GS, Bateman LM, Hebert KA, Bushee FE, Rodi SW, Gitajn IL, Ahn J, Singhal S, Martin ND, Bernthal NM, Lee C, Obremskey WT, Schoenecker JG, Elliott JT, Henderson ER. Early identification of life-threatening soft-tissue infection using dynamic fluorescence imaging: first-in-kind clinical study of first-pass kinetics. Proc SPIE Int Soc Opt Eng 2023; 12361:123610B. [PMID: 37034555 PMCID: PMC10078977 DOI: 10.1117/12.2648408] [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: 03/15/2023]
Abstract
Necrotizing soft-tissue infections (NSTIs) are aggressive and deadly. Immediate surgical debridement is standard-of-care, but patients often present with non-specific symptoms, thereby delaying treatment. Because NSTIs cause microvascular thrombosis, we hypothesized that perfusion imaging using indocyanine green (ICG) would show diminished fluorescence signal in NSTI-affected tissues, particularly compared to non-necrotizing, superficial infections. Through a first-in-kind clinical study, we performed first-pass ICG fluorescence perfusion imaging of patients with suspected NSTIs. Early results support our hypothesis that ICG signal voids occur in NSTI-affected tissues and that dynamic contrast-enhanced fluorescence parameters reveal tissue kinetics that may be related to disease progression and extent.
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Affiliation(s)
- Samuel S. Streeter
- Department of Orthopaedics, Dartmouth Health, Lebanon, NH 03756
- Geisel School of Medicine, Dartmouth College, Hanover, NH 03755
| | - Gabrielle S. Ray
- Department of Orthopaedics, Dartmouth Health, Lebanon, NH 03756
- Geisel School of Medicine, Dartmouth College, Hanover, NH 03755
| | - Logan M. Bateman
- Thayer School of Engineering, Dartmouth College, Hanover, NH 03755
| | - Kendra A. Hebert
- Thayer School of Engineering, Dartmouth College, Hanover, NH 03755
| | | | - Scott W. Rodi
- Geisel School of Medicine, Dartmouth College, Hanover, NH 03755
| | - I. Leah Gitajn
- Department of Orthopaedics, Dartmouth Health, Lebanon, NH 03756
- Geisel School of Medicine, Dartmouth College, Hanover, NH 03755
| | - Jaimo Ahn
- Michigan Medicine, U. of Michigan, Ann Arbor, MI 48109
| | - Sunil Singhal
- Perelman School of Medicine, U. of Pennsylvania, Philadelphia, PA 19104
| | - Niels D. Martin
- Perelman School of Medicine, U. of Pennsylvania, Philadelphia, PA 19104
| | - Nicholas M. Bernthal
- David Geffen School of Medicine, U. of California Los Angeles, Santa Monica, CA 90404
| | - Christopher Lee
- David Geffen School of Medicine, U. of California Los Angeles, Santa Monica, CA 90404
| | | | | | - Jonathan Thomas Elliott
- Department of Orthopaedics, Dartmouth Health, Lebanon, NH 03756
- Geisel School of Medicine, Dartmouth College, Hanover, NH 03755
- Thayer School of Engineering, Dartmouth College, Hanover, NH 03755
| | - Eric R. Henderson
- Department of Orthopaedics, Dartmouth Health, Lebanon, NH 03756
- Geisel School of Medicine, Dartmouth College, Hanover, NH 03755
- Thayer School of Engineering, Dartmouth College, Hanover, NH 03755
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6
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Elliott JT, Henderson E, Streeter SS, Demidov V, Han X, Tang Y, Sottosanti JS, Bateman L, Brůža P, Jiang S, Gitajn IL. Fluorescence-guided and molecularly-guided debridement: identifying devitalized and infected tissue in orthopaedic trauma. Proc SPIE Int Soc Opt Eng 2023; 12361:1236108. [PMID: 37056956 PMCID: PMC10091097 DOI: 10.1117/12.2661243] [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: 03/17/2023]
Abstract
Following orthopaedic trauma, bone devitalization is a critical determinant of complications such as infection or nonunion. Intraoperative assessment of bone perfusion has thus far been limited. Furthermore, treatment failure for infected fractures is unreasonably high, owing to the propensity of biofilm to form and become entrenched in poorly vascularized bone. Fluorescence-guided surgery and molecularly-guided surgery could be used to evaluate the viability of bone and soft tissue and detect the presence of planktonic and biofilm-forming bacteria. This proceedings paper discusses the motivation behind developing this technology and our most recent preclinical and clinical results.
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Affiliation(s)
- Jonathan Thomas Elliott
- Department of Orthopaedics, Dartmouth Health, 1 Medical Center Drive, Lebanon, NH 03756
- Geisel School of Medicine at Dartmouth, 1 Rope Ferry Drive, Hanover, NH USA 03755
- Thayer School of Engineering at Dartmouth, 14 Engineering Drive, Hanover, NH USA 03755
| | - Eric Henderson
- Department of Orthopaedics, Dartmouth Health, 1 Medical Center Drive, Lebanon, NH 03756
- Geisel School of Medicine at Dartmouth, 1 Rope Ferry Drive, Hanover, NH USA 03755
| | - Samuel S. Streeter
- Department of Orthopaedics, Dartmouth Health, 1 Medical Center Drive, Lebanon, NH 03756
- Geisel School of Medicine at Dartmouth, 1 Rope Ferry Drive, Hanover, NH USA 03755
| | - Valentin Demidov
- Department of Orthopaedics, Dartmouth Health, 1 Medical Center Drive, Lebanon, NH 03756
- Geisel School of Medicine at Dartmouth, 1 Rope Ferry Drive, Hanover, NH USA 03755
| | - Xinyue Han
- Thayer School of Engineering at Dartmouth, 14 Engineering Drive, Hanover, NH USA 03755
| | - Yue Tang
- Thayer School of Engineering at Dartmouth, 14 Engineering Drive, Hanover, NH USA 03755
| | - J. Scott Sottosanti
- Department of Orthopaedics, Dartmouth Health, 1 Medical Center Drive, Lebanon, NH 03756
| | - Logan Bateman
- Thayer School of Engineering at Dartmouth, 14 Engineering Drive, Hanover, NH USA 03755
| | - Petr Brůža
- Thayer School of Engineering at Dartmouth, 14 Engineering Drive, Hanover, NH USA 03755
| | - Shudong Jiang
- Thayer School of Engineering at Dartmouth, 14 Engineering Drive, Hanover, NH USA 03755
| | - I. Leah Gitajn
- Department of Orthopaedics, Dartmouth Health, 1 Medical Center Drive, Lebanon, NH 03756
- Geisel School of Medicine at Dartmouth, 1 Rope Ferry Drive, Hanover, NH USA 03755
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Tichauer KM, Diop M, Elliott JT, Samkoe KS, Hasan T, St Lawrence K, Pogue BW. Accounting for pharmacokinetic differences in dual-tracer receptor density imaging. Phys Med Biol 2014; 59:2341-51. [PMID: 24743262 DOI: 10.1088/0031-9155/59/10/2341] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Dual-tracer molecular imaging is a powerful approach to quantify receptor expression in a wide range of tissues by using an untargeted tracer to account for any nonspecific uptake of a molecular-targeted tracer. This approach has previously required the pharmacokinetics of the receptor-targeted and untargeted tracers to be identical, requiring careful selection of an ideal untargeted tracer for any given targeted tracer. In this study, methodology capable of correcting for tracer differences in arterial input functions, as well as binding-independent delivery and retention, is derived and evaluated in a mouse U251 glioma xenograft model using an Affibody tracer targeted to epidermal growth factor receptor (EGFR), a cell membrane receptor overexpressed in many cancers. Simulations demonstrated that blood, and to a lesser extent vascular-permeability, pharmacokinetic differences between targeted and untargeted tracers could be quantified by deconvolving the uptakes of the two tracers in a region of interest devoid of targeted tracer binding, and therefore corrected for, by convolving the uptake of the untargeted tracer in all regions of interest by the product of the deconvolution. Using fluorescently labeled, EGFR-targeted and untargeted Affibodies (known to have different blood clearance rates), the average tumor concentration of EGFR in four mice was estimated using dual-tracer kinetic modeling to be 3.9 ± 2.4 nM compared to an expected concentration of 2.0 ± 0.4 nM. However, with deconvolution correction a more equivalent EGFR concentration of 2.0 ± 0.4 nM was measured.
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Affiliation(s)
- K M Tichauer
- Biomedical Engineering, Illinois Institute of Technology, Chicago, IL 60616, USA
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8
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Elliott JT. Transparency and the foundations of the health service. BMJ 2013; 346:f2507. [PMID: 23618843 DOI: 10.1136/bmj.f2507] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
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9
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Arora R, Ridha M, Lee DS, Elliott JT, Rosenberg H, St Lawrence K. Changes in Cerebral Hemodynamics in Response to Medical Therapy for Patent Ductus Arteriosus: Prediction of Treatment Outcome in Preterm Infants. Paediatr Child Health 2012. [DOI: 10.1093/pch/17.suppl_a.38a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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10
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Elliott JT, Tona A, Woodward JT, Meuse CW, Elgendy HM, Plant AL. Osteoblast cell membrane hybrid bilayers for studying cell–cell interactions. ACTA ACUST UNITED AC 2004; 151:75-81. [PMID: 16475847 DOI: 10.1049/ip-nbt:20040640] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Osteoblast-like cells were grown on a surface that presents cell membrane components to the cells in culture. The culture surface was a bimolecular layer formed by the interaction of osteoblast plasma membrane vesicles with an alkanethiol monolayer. The potential of these osteoblast-membrane hybrid bilayers for promoting osteoblast adhesion, growth and differentiation was examined. UMR-106 osteoblast-like cells cultured on these surfaces are normal in appearance, and in the presence of serum, proliferate as well or better than on control surfaces. The level of alkaline phosphatase production in the presence and absence of serum suggests that the osteoblast-like cells retain their differentiated phenotype, and appear to respond to the cell surface ligands presented by the osteoblast-membrane biomimetic surface. These observations suggest that biomimetic membrane films prepared from osteoblast cell membranes support osteoblast cell growth, allow the cells to maintain their differentiation state and may be suitable as a model system to probe cell-cell interactions.
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Affiliation(s)
- J T Elliott
- Biotechnology Division, National Institute of Standards and Technology, Gaithersburg, USA
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11
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Elliott JT, Hoekstra WJ, Derian CK, Addo MF, Maryanoff BE, Ahern DG, Prestwich GD. Tritiated photoactivatable analogs of the native human thrombin receptor (PAR-1) agonist peptide, SFLLRN-NH2. J Pept Res 2001; 57:494-506. [PMID: 11437953 DOI: 10.1034/j.1399-3011.2001.00857.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Six photoactivatable analogs of the human thrombin receptor activating peptide (TRAP), SFLLRN-NH2, were synthesized by substituting the photoactive amino acid, p-benzoylphenylalanine (Bpa), into each position of the peptide sequence. Platelet aggregation assays indicated that the peptides with Bpa substitutions at positions 3 to 6 retained agonist activity. These peptides were prepared in tritiated form as potential thrombin receptor photoaffinity labels. The [3H]Bpa-containing analogs were constructed by resynthesizing the peptides with the amino acid, 4-benzoyl-2',5'-dibromophenylalanine (Br2Bpa), and subjecting the purified peptides to Pd-catalyzed tritiodebromination. The radiochemical yields for the reductive tritiation were < 2% for peptides with [3H]Bpa in the third and fourth positions, and between 7 and 16% for the peptides with substitutions at the fifth and sixth positions. The low yields were due to over-reduction of the Bpa carbonyl group and nonspecific degradation during reductive tritiation. This report describes the first use of Br2Bpa for the preparation of tritiated photoactivatable peptides.
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Affiliation(s)
- J T Elliott
- Department of Physiology and Biophysics, The University of at Stony Brook, Stony Brook, New York, USA
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12
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Gatzoulis MA, Elliott JT, Guru V, Siu SC, Warsi MA, Webb GD, Williams WG, Liu P, McLaughlin PR. Right and left ventricular systolic function late after repair of tetralogy of Fallot. Am J Cardiol 2000; 86:1352-7. [PMID: 11113412 DOI: 10.1016/s0002-9149(00)01241-8] [Citation(s) in RCA: 77] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Right ventricular (RV) dysfunction has adverse effects on long-term outcome in patients with repaired tetralogy of Fallot (TOF). We employed serial radionuclide angiography (RNA) to examine RV and left ventricular (LV) systolic function in adults late after TOF repair and its relation to clinical outcome. We reviewed 10-year records of 95 patients (53 men) with TOF followed in our clinic (mean age at repair 12.6 +/- 10.5 years, mean age at last follow-up 37.7 +/- 9.8 years) who underwent at least 2 RNAs between 1987 and 1997. Most patients were well by the end of the study (80% were New York Heart Association class I, 17% were class II, and 3% were in class III). Sixteen patients experienced sustained tachyarrhythmias (8 had atrial; 8 patients had ventricular). One patient died suddenly. Fifteen patients underwent RV outflow reoperations (15 underwent pulmonary valve replacement; 7 had relief of RV outflow obstruction); RV systolic function during exercise in these 15 patients was significantly impaired before and returned to similar levels after surgery, compared with the rest of the patients. Overall, RV and LV function remained stable in the whole group at a mean interval of 5.7 +/- 2.2 years between first and last RNA. This group of closely followed adults with TOF remained well over 10 years with a low incidence of sudden death and stable RV and LV systolic function, despite a relatively large number of RV outflow reoperations. Aggressive intervention for right-sided hemodynamic abnormalities may have contributed to this outcome. Preserved ventricular function may herald a favorable long-term outlook in this group.
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Affiliation(s)
- M A Gatzoulis
- Department of Medicine, University of Toronto Congenital Cardiac Centre for Adults, University Health Network, University of Toronto, Ontario, Canada.
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Abstract
Two maleimide-containing diacylglycerol derivatives were synthesized to permit the anchoring of short peptides and longer polypeptides to phospholipid bilayers and membranes. The maleimide was introduced at the site normally occupied by a phospholipid headgroup. The first lipid, the dipalmitoyl ester of 1-maleimido-2,3-propanediol, was developed as a membrane anchor for extracellular domains of transmembrane proteins. The second anchoring lipid, in which the 3-position contained a 6-aminohexanoate, was designed for convenient modification with amine-reactive reporter groups. Specifically, the NBD fluorophore, 7-nitrobenzo-2-oxa-1, 3-diazole-aminohexanoic-N-hydroxysuccinimide ester, was attached to give an fluorescent anchoring reagent. Next, these reagents were applied to the anchoring of a C-terminally cysteamine-modified 8 kDa polypeptide that comprises the extracellular N-terminal domain of the human thrombin receptor, a transmembrane protease-activated receptor (PAR-1). Gel filtration and fluorescence analysis showed that the fluorescent lipopolypeptide spontaneously inserted into preformed phospholipid vesicles, but it did not insert into whole cell membranes. In contrast, the dipalmitoyl derivative could only be reconstituted into artificial membranes by mixing the lipopolypeptide and phospholipid before vesicle formation. These results suggest that biophysical interactions governing the lipopolypeptide insertion into artificial and cellular membranes may differ. The thiol-reactive lipidating reagents should be valuable materials for studying the structure and function of peptides and polypeptides at phospholipid bilayer surfaces.
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Affiliation(s)
- J T Elliott
- Department of Physiology and Biophysics, The University at Stony Brook, Stony Brook, New York, USA
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Wang T, Pentyala S, Elliott JT, Dowal L, Gupta E, Rebecchi MJ, Scarlata S. Selective interaction of the C2 domains of phospholipase C-beta1 and -beta2 with activated Galphaq subunits: an alternative function for C2-signaling modules. Proc Natl Acad Sci U S A 1999; 96:7843-6. [PMID: 10393909 PMCID: PMC22149 DOI: 10.1073/pnas.96.14.7843] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Phospholipase C (PLC)-beta1 and PLC-beta2 are regulated by the Gq family of heterotrimeric G proteins and contain C2 domains. These domains are Ca2+-binding modules that serve as membrane-attachment motifs in a number of signal transduction proteins. To determine the role that C2 domains play in PLC-beta1 and PLC-beta2 function, we measured the binding of the isolated C2 domains to membrane bilayers. We found, unexpectedly, that these modules do not bind to membranes but they associate strongly and specifically to activated [guanosine 5'-[gamma-thio]triphosphate (GTP[gammaS])-bound] Galphaq subunits. The C2 domain of PLC-beta1 effectively suppressed the activation of the intact isozyme by Galphaq(GTP[gammaS]), indicating that the C2-Galphaq interaction may be physiologically relevant. C2 affinity for Galphaq(GTP[gammaS]) was reduced when Galphaq was deactivated to the GDP-bound state. Binding to activated Galphai1 subunits or to Gbetagamma subunits was not detected. Also, Galphaq(GTP[gammaS]) failed to associate with the C2 domain of PLC-delta, an isozyme that is not activated by Galphaq. These results indicate that the C2 domains of PLC-beta1 and PLC-beta2 provide a surface to which Galphaq subunits can dock, leading to activation of the native protein.
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Affiliation(s)
- T Wang
- Department of Physiology and Biophysics, State University of New York, Stony Brook, NY 11794-8661, USA
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Elliott JT, Hoekstra WJ, Maryanoff BE, Prestwich GD. Photoactivatable peptides based on BMS-197525: a potent antagonist of the human thrombin receptor (PAR-1). Bioorg Med Chem Lett 1999; 9:279-84. [PMID: 10021945 DOI: 10.1016/s0960-894x(98)00730-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Photoactivatable analogs of the human thrombin receptor (PAR-1) antagonist, N-trans-cinnamoyl-p-fluoroPhe-p-guanidinoPhe-Leu-Arg-NH2 (BMS-197525), were prepared with benzophenone substitutions in the N-terminal, Leu, or Arg position. The analogs retained antagonist activity (with reduced potency); the tritium-labeled isotopomers are potential photoaffinity labels for the receptor. C-Terminal extension of the analogs with ornithine(biotin) did not significantly alter antagonist potency.
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Affiliation(s)
- J T Elliott
- Department of Physiology and Biophysics, University at Stony Brook, NY 11794, USA
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Abstract
A photoaffinity analog of Helicoverpa zea pheromone biosynthesis activating neuropeptide (Hez-PBAN) was used to identify PBAN binding proteins in various tissues of the corn earworm moth, H. zea. Synthetic Hez-PBAN was derivatized on Lys-27 with p-benzoyldihydrocinnamoyl-N-hydroxysuccinimide ester (BZDC-NHS ester). The resulting BZDC-PBAN stimulated pheromone production in H. zea isolated abdomens at levels comparable to those of the unmodified peptide. Photoaffinity labeling experiments using [3H]BZDC-PBAN with female moth tissues revealed soluble 100 and 115 kDa proteins in the brain-subesophageal ganglia complex, ventral nerve cord, and thoracic muscle that were specifically labeled with the PBAN analog.
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Affiliation(s)
- J T Elliott
- Department of Physiology and Biophysics, The University at Stony Brook, New York 11794-8661, USA
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Mehrotra B, Elliott JT, Chen J, Olszewski JD, Profit AA, Chaudhary A, Fukuda M, Mikoshiba K, Prestwich GD. Selective photoaffinity labeling of the inositol polyphosphate binding C2B domains of synaptotagmins. J Biol Chem 1997; 272:4237-44. [PMID: 9020139 DOI: 10.1074/jbc.272.7.4237] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.2] [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: 02/03/2023] Open
Abstract
Synaptotagmin (Syt) II, a synaptic vesicle protein containing two copies of highly conserved protein kinase C homology regions known as the C2A and C2B domains, acts as a Ca2+ sensor and provides both phospholipid and inositol polyphosphate (IPn) recognition domains important in endo- and exocytosis. Four photoaffinity analogues of IP3, IP4, and IP6 containing a P-1- or P-2-linked 4-benzoyldihydrocinnamidyl (BZDC) photophore were used to label glutathione S-transferase (GST) fusion constructs of the Syt II-C2A and C2B domains. The P-2-linked [3H]BZDC-IP6 showed efficient, IP6-displaceable labeling of the GST-Syt II-C2B. The rank order of photocovalent modification paralleled the order of competitive displacement: IP6 (P-2-linked) > IP4 > IP3. The P-1-linked [3H]BZDC-IP6 failed to label the C2B domains. The GST-Syt III-C2B domain, which lacks IP6 binding affinity, also failed to undergo labeling by P-2-linked [3H]BZDC-IP6. When mixtures of the 32-amino acid basic peptide corresponding to the essential IPn binding region of the Syt II-C2B domain and GST-Syt II-C2B were labeled by a stoichiometric amount of P-2-linked [3H]BZDC-IP6, the two polypeptides showed equivalent affinity for the photolabel. Although the CD spectrum of this 32-mer at two pH values showed a random coil, the photoaffinity analogue of IP6 appeared to induce a binding-compatible structure in the short peptide.
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Affiliation(s)
- B Mehrotra
- Departments of Chemistry, Biochemistry and Cell Biology, University at Stony Brook, Stony Brook, New York 11794-3400, USA
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Abstract
Benzophenones (BP) and related aryl ketone photophores have become established as the photoactivatable group of choice for high-efficiency covalent modification of hydrophobic regions of binding proteins, including enzymes and receptors that recognize peptide hormones, (oligo) nucleotides and nucleosides, phosphoinositides, inositol polyphosphates and a wide variety of therapeutic molecules. This review presents the advantages of BP as photoaffinity labels and provides specific examples from the last 3 years of applications of BP-containing ligands used in biochemistry.
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Affiliation(s)
- G D Prestwich
- Department of Chemistry, University at Stony Brook, NY, USA.
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Olszewski JD, Dormán G, Elliott JT, Hong Y, Ahern DG, Prestwich GD. Tethered benzophenone reagents for the synthesis of photoactivatable ligands. Bioconjug Chem 1995; 6:395-400. [PMID: 7578359 DOI: 10.1021/bc00034a009] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
A new radiolabeled, bifunctional photoaffinity cross-linking reagent, N-succinimidyl p-benzoyl-[2,3-3H2]dihydrocinnamate, has been synthesized in high yield and with high specific activity. This reagent can be used to append the benzophenone photophore to amino groups of small molecules, such as O-aminoalkylinositol polyphosphates and polypeptides. The resulting tritiated photoaffinity labels can be purified and manipulated in ambient light and can be activated at 360 nm.
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Affiliation(s)
- J D Olszewski
- Department of Chemistry, University at Stony Brook, New York 11794-3400, USA
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Gidh-Jain M, Zhang Y, van Poelje PD, Liang JY, Huang S, Kim J, Elliott JT, Erion MD, Pilkis SJ, Raafat el-Maghrabi M. The allosteric site of human liver fructose-1,6-bisphosphatase. Analysis of six AMP site mutants based on the crystal structure. J Biol Chem 1994; 269:27732-8. [PMID: 7961695] [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: 01/28/2023] Open
Abstract
The molecular structure of human liver fructose-1,6-bisphosphatase complexed with AMP was determined by x-ray diffraction using molecular replacement, starting from the pig kidney enzyme AMP complex. Of the 34 amino acid residues which differ between these two sequences, only one interacts with AMP; Met30 in pig kidney is Leu30 in human liver. From this analysis, six sites in which side chains of amino acid residues are in contact with AMP, Ala24, Leu30, Thr31, Tyr113, Arg140, and Met177, were mutated by polymerase chain reaction. The wild-type and mutant forms were expressed in Escherichia coli, purified, and their kinetic properties determined. Circular dichroism spectra of the mutants were indistinguishable from that of the wild-type enzyme. Kinetic analyses revealed that all forms had similar turnover numbers, Km values for fructose 2,6-bisphosphate, and inhibition constants for fructose 2,6-bisphosphate. Apparent Ki values for AMP inhibition of the Leu30 --> Phe and Met177 --> Ala mutants were similar to those of the wild-type enzyme, but the apparent Ki values for the Arg140 --> Ala and Ala24 --> Phe mutants were 7-to 20-fold higher, respectively. The Thr31 --> Ser mutant exhibited a 5-fold increase in apparent Ki for AMP, while mutation of Thr31 to Ala increased the apparent Ki 120-fold. AMP inhibition of the Tyr113 --> Phe mutant was undetectable even at millimolar AMP concentrations. Fructose 2,6-bisphosphate potentiated AMP inhibition of the mutants to the same extent as for the wild-type enzyme, except in the case of the Thr31 --> Ala and Tyr113 --> Phe mutants. Thus, the Met177 --> Ala mutant suggests that the side chain beyond C alpha is not needed for AMP binding, and that the Leu30 --> Phe mutant preserves the AMP contacts with these side chains. Thr31, Tyr113, and Arg140 form key hydrogen bonds to AMP consistent with strong side chain interactions in the wild-type enzyme. Finally, the absence of any effect of fructose 2,6-bisphosphate on AMP inhibition observed in the Thr31 --> Ala mutant may be an important clue relating to the mechanism of synergism of these two inhibitors.
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Affiliation(s)
- M Gidh-Jain
- Department of Physiology and Biophysics, State University of New York at Stony Brook 11794-8861
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Gidh-Jain M, Zhang Y, van Poelje PD, Liang JY, Huang S, Kim J, Elliott JT, Erion MD, Pilkis SJ, Raafat el-Maghrabi M. The allosteric site of human liver fructose-1,6-bisphosphatase. Analysis of six AMP site mutants based on the crystal structure. J Biol Chem 1994. [DOI: 10.1016/s0021-9258(18)47047-0] [Citation(s) in RCA: 63] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
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