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Tsarova K, Morgan AE, Melendres-Groves L, Ibrahim MM, Ma CL, Pan IZ, Hatton ND, Beck EM, Ferrel MN, Selzman CH, Ingram D, Alamri AK, Ratcliffe MB, Wilson BD, Ryan JJ. Imaging in Pulmonary Vascular Disease-Understanding Right Ventricle-Pulmonary Artery Coupling. Compr Physiol 2022; 12:3705-3730. [PMID: 35950653 DOI: 10.1002/cphy.c210017] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The right ventricle (RV) and pulmonary arterial (PA) tree are inextricably linked, continually transferring energy back and forth in a process known as RV-PA coupling. Healthy organisms maintain this relationship in optimal balance by modulating RV contractility, pulmonary vascular resistance, and compliance to sustain RV-PA coupling through life's many physiologic challenges. Early in states of adaptation to cardiovascular disease-for example, in diastolic heart failure-RV-PA coupling is maintained via a multitude of cellular and mechanical transformations. However, with disease progression, these compensatory mechanisms fail and become maladaptive, leading to the often-fatal state of "uncoupling." Noninvasive imaging modalities, including echocardiography, magnetic resonance imaging, and computed tomography, allow us deeper insight into the state of coupling for an individual patient, providing for prognostication and potential intervention before uncoupling occurs. In this review, we discuss the physiologic foundations of RV-PA coupling, elaborate on the imaging techniques to qualify and quantify it, and correlate these fundamental principles with clinical scenarios in health and disease. © 2022 American Physiological Society. Compr Physiol 12: 1-26, 2022.
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Affiliation(s)
- Katsiaryna Tsarova
- Division of Cardiovascular Medicine, Department of Medicine, University of Utah School of Medicine, Salt Lake City, Utah, USA
| | - Ashley E Morgan
- Division of Cardiothoracic Surgery, Department of Surgery, University of Utah, Salt Lake City, Utah, USA
| | - Lana Melendres-Groves
- Division of Pulmonary and Critical Care Medicine, University of New Mexico, Albuquerque, New Mexico, USA
| | - Majd M Ibrahim
- Division of Cardiovascular Medicine, Department of Medicine, University of Utah School of Medicine, Salt Lake City, Utah, USA
| | - Christy L Ma
- Division of Cardiovascular Medicine, Department of Medicine, University of Utah School of Medicine, Salt Lake City, Utah, USA
| | - Irene Z Pan
- Department of Pharmacy, University of Utah Health, Salt Lake City, Utah, USA
| | - Nathan D Hatton
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, University of Utah, Salt Lake City, Utah, USA
| | - Emily M Beck
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, University of Utah, Salt Lake City, Utah, USA
| | - Meganne N Ferrel
- Division of Cardiovascular Medicine, Department of Medicine, University of Utah School of Medicine, Salt Lake City, Utah, USA
| | - Craig H Selzman
- Division of Cardiothoracic Surgery, Department of Surgery, University of Utah, Salt Lake City, Utah, USA
| | - Dominique Ingram
- Division of Cardiovascular Medicine, Department of Medicine, University of Utah School of Medicine, Salt Lake City, Utah, USA
| | - Ayedh K Alamri
- Department of Medicine, University of Utah, Salt Lake City, Utah, USA
| | | | - Brent D Wilson
- Division of Cardiovascular Medicine, Department of Medicine, University of Utah School of Medicine, Salt Lake City, Utah, USA
| | - John J Ryan
- Division of Cardiovascular Medicine, Department of Medicine, University of Utah School of Medicine, Salt Lake City, Utah, USA
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Orkild BA, Zenger B, Iyer K, Rupp LC, Ibrahim MM, Khashani AG, Perez MD, Foote MD, Bergquist JA, Morris AK, Kim JJ, Steinberg BA, Selzman C, Ratcliffe MB, MacLeod RS, Elhabian S, Morgan AE. All Roads Lead to Rome: Diverse Etiologies of Tricuspid Regurgitation Create a Predictable Constellation of Right Ventricular Shape Changes. Front Physiol 2022; 13:908552. [PMID: 35860653 PMCID: PMC9291517 DOI: 10.3389/fphys.2022.908552] [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] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2022] [Accepted: 05/16/2022] [Indexed: 11/17/2022] Open
Abstract
Introduction: Myriad disorders cause right ventricular (RV) dilation and lead to tricuspid regurgitation (TR). Because the thin-walled, flexible RV is mechanically coupled to the pulmonary circulation and the left ventricular septum, it distorts with any disturbance in the cardiopulmonary system. TR, therefore, can result from pulmonary hypertension, left heart failure, or intrinsic RV dysfunction; but once it occurs, TR initiates a cycle of worsening RV volume overload, potentially progressing to right heart failure. Characteristic three-dimensional RV shape-changes from this process, and changes particular to individual TR causes, have not been defined in detail. Methods: Cardiac MRI was obtained in 6 healthy volunteers, 41 patients with ≥ moderate TR, and 31 control patients with cardiac disease without TR. The mean shape of each group was constructed using a three-dimensional statistical shape model via the particle-based shape modeling approach. Changes in shape were examined across pulmonary hypertension and congestive heart failure subgroups using principal component analysis (PCA). A logistic regression approach based on these PCA modes identified patients with TR using RV shape alone. Results: Mean RV shape in patients with TR exhibited free wall bulging, narrowing of the base, and blunting of the RV apex compared to controls (p < 0.05). Using four primary PCA modes, a logistic regression algorithm identified patients with TR correctly with 82% recall and 87% precision. In patients with pulmonary hypertension without TR, RV shape was narrower and more streamlined than in healthy volunteers. However, in RVs with TR and pulmonary hypertension, overall RV shape continued to demonstrate the free wall bulging characteristic of TR. In the subgroup of patients with congestive heart failure without TR, this intermediate state of RV muscular hypertrophy was not present. Conclusion: The multiple causes of TR examined in this study changed RV shape in similar ways. Logistic regression classification based on these shape changes reliably identified patients with TR regardless of etiology. Furthermore, pulmonary hypertension without TR had unique shape features, described here as the "well compensated" RV. These results suggest shape modeling as a promising tool for defining severity of RV disease and risk of decompensation, particularly in patients with pulmonary hypertension.
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Affiliation(s)
- Benjamin A. Orkild
- Scientific Computing and Imaging Institute, University of Utah, Salt Lake City, UT, United States
- Department of Biomedical Engineering, University of Utah, Salt Lake City, UT, United States
| | - Brian Zenger
- Scientific Computing and Imaging Institute, University of Utah, Salt Lake City, UT, United States
- Department of Biomedical Engineering, University of Utah, Salt Lake City, UT, United States
| | - Krithika Iyer
- Scientific Computing and Imaging Institute, University of Utah, Salt Lake City, UT, United States
- School of Computing, University of Utah, Salt Lake City, UT, United States
| | - Lindsay C. Rupp
- Scientific Computing and Imaging Institute, University of Utah, Salt Lake City, UT, United States
- Department of Biomedical Engineering, University of Utah, Salt Lake City, UT, United States
| | - Majd M Ibrahim
- Division of Cardiovascular Medicine, University of Utah, Salt Lake City, UT, United States
| | - Atefeh G. Khashani
- Scientific Computing and Imaging Institute, University of Utah, Salt Lake City, UT, United States
| | - Maura D. Perez
- Scientific Computing and Imaging Institute, University of Utah, Salt Lake City, UT, United States
| | - Markus D. Foote
- Scientific Computing and Imaging Institute, University of Utah, Salt Lake City, UT, United States
- Department of Biomedical Engineering, University of Utah, Salt Lake City, UT, United States
| | - Jake A. Bergquist
- Scientific Computing and Imaging Institute, University of Utah, Salt Lake City, UT, United States
- Department of Biomedical Engineering, University of Utah, Salt Lake City, UT, United States
| | - Alan K. Morris
- Scientific Computing and Imaging Institute, University of Utah, Salt Lake City, UT, United States
| | - Jiwon J. Kim
- Weill-Cornell Medical College, Division of Cardiology, New York, NY, United States
| | - Benjamin A. Steinberg
- Division of Cardiovascular Medicine, University of Utah, Salt Lake City, UT, United States
| | - Craig Selzman
- Division of Cardiothoracic Surgery, University of Utah, Salt Lake City, UT, United States
| | - Mark B. Ratcliffe
- Department of Surgery, The San Francisco VA Medical Center, University of California, San Francisco, San Francisco, CA, United States
| | - Rob S. MacLeod
- Scientific Computing and Imaging Institute, University of Utah, Salt Lake City, UT, United States
- Department of Biomedical Engineering, University of Utah, Salt Lake City, UT, United States
| | - Shireen Elhabian
- Scientific Computing and Imaging Institute, University of Utah, Salt Lake City, UT, United States
- School of Computing, University of Utah, Salt Lake City, UT, United States
- *Correspondence: Ashley E. Morgan, ; Shireen Elhabian,
| | - Ashley E. Morgan
- St. Luke’s Medical Center Cardiothoracic and Vascular Surgery, Boise, ID, United States
- *Correspondence: Ashley E. Morgan, ; Shireen Elhabian,
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Zhang Y, Adams J, Wang VY, Horwitz L, Tartibi M, Morgan AE, Kim J, Wallace AW, Weinsaft JW, Ge L, Ratcliffe MB. A finite element model of the cardiac ventricles with coupled circulation: Biventricular mesh generation with hexahedral elements, airbags and a functional mockup interface to the circulation. Comput Biol Med 2021; 137:104840. [PMID: 34508972 DOI: 10.1016/j.compbiomed.2021.104840] [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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Revised: 08/11/2021] [Accepted: 08/31/2021] [Indexed: 10/20/2022]
Abstract
INTRODUCTION Finite element (FE) mechanics models of the heart are becoming more sophisticated. However, there is lack of consensus about optimal element type and coupling of FE models to the circulation. We describe biventricular (left (LV) and right (RV) ventricles) FE mechanics model creation using hexahedral elements, airbags and a functional mockup interface (FMI) to lumped-parameter models of the circulation. METHODS Cardiac MRI (CMR) was performed in two healthy volunteers and a single patient with ischemic heart disease (IHD). CMR images were segmented and surfaced, meshing with hexahedral elements was performed with a "thin butterfly with septum" topology. LV and RV inflow and outflow airbags were coupled to lumped-parameter circulation models with an FMI interface. Pulmonary constriction (PAC) and vena cava occlusion (VCO) were simulated and end-systolic pressure-volume relations (ESPVR) were calculated. RESULTS Mesh construction was prompt with representative contouring and mesh adjustment requiring 32 and 26 min Respectively. The numbers of elements ranged from 4104 to 5184 with a representative Jacobian of 1.0026 ± 0.4531. Agreement between CMR-based surfaces and mesh was excellent with root-mean-squared error of 0.589 ± 0.321 mm. The LV ESPVR slope was 3.37 ± 0.09 in volunteers but 2.74 in the IHD patient. The effect of PAC and VCO on LV ESPVR was consistent with ventricular interaction (p = 0.0286). CONCLUSION Successful co-simulation using a biventricular FE mechanics model with hexahedral elements, airbags and an FMI interface to lumped-parameter model of the circulation was demonstrated. Future studies will include comparison of element type and study of cardiovascular pathologies and device therapies.
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Affiliation(s)
- Yue Zhang
- Department of Surgery, University of California, San Francisco, CA, USA; Department of Bioengineering, University of California, San Francisco, CA, USA; San Francisco Veterans Affairs Medical Center, San Francisco, CA, USA
| | - Jennifer Adams
- School of Medicine, University of Texas Rio Grande Valley, Edinburg, TX, USA
| | - Vicky Y Wang
- Department of Surgery, University of California, San Francisco, CA, USA; Department of Bioengineering, University of California, San Francisco, CA, USA; San Francisco Veterans Affairs Medical Center, San Francisco, CA, USA
| | - Lucas Horwitz
- San Francisco Veterans Affairs Medical Center, San Francisco, CA, USA
| | | | - Ashley E Morgan
- Department of Surgery, University of Utah, Salt Lake City, UT, USA
| | - Jiwon Kim
- Department of Medicine, Weill Cornell Medicine, New York, NY, USA
| | - Arthur W Wallace
- Department of Anesthesia, University of California, San Francisco, CA, USA; San Francisco Veterans Affairs Medical Center, San Francisco, CA, USA
| | | | - Liang Ge
- Department of Surgery, University of California, San Francisco, CA, USA; Department of Bioengineering, University of California, San Francisco, CA, USA; San Francisco Veterans Affairs Medical Center, San Francisco, CA, USA
| | - Mark B Ratcliffe
- Department of Surgery, University of California, San Francisco, CA, USA; Department of Bioengineering, University of California, San Francisco, CA, USA; San Francisco Veterans Affairs Medical Center, San Francisco, CA, USA.
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Morgan AE, Kashani A, Zenger B, Rupp LC, Perez MD, Foote MD, Morris AK, Ratcliffe MB, Kim JJ, Weinsaft JW, Sharma V, MacLeod RS, Elhabian S. Right Ventricular Shape Distortion in Tricuspid Regurgitation. Comput Cardiol (2010) 2020; 47:10.22489/cinc.2020.346. [PMID: 33778088 PMCID: PMC7992117 DOI: 10.22489/cinc.2020.346] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Tricuspid regurgitation (TR) is a failure in right-sided AV valve function which, if left untreated, leads to marked cardiac shape changes and heart failure. However, the specific right ventricular shape changes resulting from TR are unknown. The goal of this study is to characterize the RV shape changes of patients with severe TR. RVs were segmented from CINE MRI images. Using particle-based shape modeling (PSM), a dense set of homologous landmarks were placed with geometric consistency on the endocardial surface of each RV, via an entropy-based optimization of the information content of the shape model. Principal component analysis (PCA) identified the significant modes of shape variation across the population. These modes were used to create a patient-prediction model. 32 patients and 6 healthy controls were studied. The mean RV shape of TR patients demonstrated increased sphericity relative to controls, with the three most dominant modes of variation showing significant widening of the short axis of the heart, narrowing of the base at the RV outflow tract (RVOT), and blunting of the RV apex. By PCA, shape changes based on the first three modes of variation correctly identified patient vs. control hearts 86.5% of the time. The shape variation may further illuminate the mechanics of TR-induced RV failure and recovery, providing potential targets for therapies including novel devices and surgical interventions.
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Affiliation(s)
| | | | | | | | | | | | | | - Mark B Ratcliffe
- University of California, San Francisco, and the San Francisco VA Medical Center
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Zhang Y, Wang VY, Morgan AE, Kim J, Ge L, Guccione JM, Weinsaft JW, Ratcliffe MB. A Novel MRI-Based Finite Element Modeling Method for Calculation of Myocardial Ischemia Effect in Patients With Functional Mitral Regurgitation. Front Physiol 2020; 11:158. [PMID: 32231584 PMCID: PMC7082816 DOI: 10.3389/fphys.2020.00158] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2019] [Accepted: 02/12/2020] [Indexed: 11/16/2022] Open
Abstract
BACKGROUND Functional Mitral Regurgitation (FMR) associated with coronary artery disease affects nearly 3 million patients in the United States. Both myocardial infarction (MI) and ischemia contribute to FMR development but uncertainty as to which patients will respond to revascularization (REVASC) of ischemia alone prevents rational decision making about FMR therapy. The aim of this study was to create patient-specific cardiac MRI (CMR) informed finite element (FE) models of the left ventricle (LV), calculate regional LV systolic contractility and then use optimized systolic material properties to simulate the effect of revascularization (virtual REVASC). METHODS We describe a novel FE method able to predict the effect of myocardial ischemia on regional LV function. CMR was obtained in five patients with multi-vessel coronary disease and FMR before and 3 months after percutaneous REVASC and a single healthy volunteer. Patient-specific FE models were created and divided into 17 sectors where the systolic contractility parameter, T m a x of each sector was a function of regional stress perfusion (SP-CMR) and myocardial infarction (LGE-CMR) scores. Sector-specific circumferential and longitudinal end-systolic strain and LV volume from CSPAMM were used in a formal optimization to determine the sector based myocardial contractility, T m a x and ischemia effect, α. Virtual REVASC was simulated by setting α to zero. RESULTS The FE optimization successfully converged with good agreement between calculated and experimental end-systolic strain and LV volumes. Specifically, the optimized T max for the healthy myocardium for five patients and the volunteer was 495.1, 336.8, 173.5, 227.9, 401.4, and 218.9 kPa. The optimized α was found to be 1.0, 0.44, and 0.08 for Patients 1, 2, and 3, and 0 for Patients 4 and 5. The calculated average of radial strain for Patients 1, 2, and 3 at baseline and after virtual REVASC was 0.23 and 0.25, respectively. CONCLUSION We developed a novel computational method able to predict the effect of myocardial ischemia in patients with FMR. This method can be used to predict the effect of ischemia on the regional myocardium and promises to facilitate better understanding of FMR response to REVASC.
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Affiliation(s)
- Yue Zhang
- San Francisco Veterans Affairs Medical Center, San Francisco, CA, United States
- Department of Surgery, University of California, San Francisco, San Francisco, CA, United States
- Department of Bioengineering, University of California, San Francisco, San Francisco, CA, United States
| | - Vicky Y. Wang
- San Francisco Veterans Affairs Medical Center, San Francisco, CA, United States
- Department of Surgery, University of California, San Francisco, San Francisco, CA, United States
- Department of Bioengineering, University of California, San Francisco, San Francisco, CA, United States
| | - Ashley E. Morgan
- Department of Surgery, University of California, San Francisco, San Francisco, CA, United States
| | - Jiwon Kim
- Department of Medicine, Weill Cornell Medicine, New York, NY, United States
| | - Liang Ge
- San Francisco Veterans Affairs Medical Center, San Francisco, CA, United States
- Department of Surgery, University of California, San Francisco, San Francisco, CA, United States
- Department of Bioengineering, University of California, San Francisco, San Francisco, CA, United States
| | - Julius M. Guccione
- San Francisco Veterans Affairs Medical Center, San Francisco, CA, United States
- Department of Surgery, University of California, San Francisco, San Francisco, CA, United States
- Department of Bioengineering, University of California, San Francisco, San Francisco, CA, United States
| | | | - Mark B. Ratcliffe
- San Francisco Veterans Affairs Medical Center, San Francisco, CA, United States
- Department of Surgery, University of California, San Francisco, San Francisco, CA, United States
- Department of Bioengineering, University of California, San Francisco, San Francisco, CA, United States
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Zhang Y, Wang VY, Morgan AE, Kim J, Handschumacher MD, Moskowitz CS, Levine RA, Ge L, Guccione JM, Weinsaft JW, Ratcliffe MB. Mechanical effects of MitraClip on leaflet stress and myocardial strain in functional mitral regurgitation - A finite element modeling study. PLoS One 2019; 14:e0223472. [PMID: 31600276 PMCID: PMC6786765 DOI: 10.1371/journal.pone.0223472] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2019] [Accepted: 09/23/2019] [Indexed: 11/18/2022] Open
Abstract
Purpose MitraClip is the sole percutaneous device approved for functional mitral regurgitation (MR; FMR) but MR recurs in over one third of patients. As device-induced mechanical effects are a potential cause for MR recurrence, we tested the hypothesis that MitraClip increases leaflet stress and procedure-related strain in sub-valvular left ventricular (LV) myocardium in FMR associated with coronary disease (FMR-CAD). Methods Simulations were performed using finite element models of the LV + mitral valve based on MRI of 5 sheep with FMR-CAD. Models were modified to have a 20% increase in LV volume (↑LV_VOLUME) and MitraClip was simulated with contracting beam elements (virtual sutures) placed between nodes in the center edge of the anterior (AL) and posterior (PL) mitral leaflets. Effects of MitraClip on leaflet stress in the peri-MitraClip region of AL and PL, septo-lateral annular diameter (SLAD), and procedure-related radial strain (Err) in the sub-valvular myocardium were calculated. Results MitraClip increased peri-MitraClip leaflet stress at end-diastole (ED) by 22.3±7.1 kPa (p<0.0001) in AL and 14.8±1.2 kPa (p<0.0001) in PL. MitraClip decreased SLAD by 6.1±2.2 mm (p<0.0001) and increased Err in the sub-valvular lateral LV myocardium at ED by 0.09±0.04 (p<0.0001)). Furthermore, MitraClip in ↑LV_VOLUME was associated with persistent effects at ED but also at end-systole where peri-MitraClip leaflet stress was increased in AL by 31.9±14.4 kPa (p = 0.0268) and in PL by 22.5±23.7 kPa (p = 0.0101). Conclusions MitraClip for FMR-CAD increases mitral leaflet stress and radial strain in LV sub-valvular myocardium. Mechanical effects of MitraClip are augmented by LV enlargement.
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Affiliation(s)
- Yue Zhang
- San Francisco Veterans Affairs Medical Center, San Francisco, CA, United States of America
- Department of Surgery, University of California, San Francisco, CA, United States of America
| | - Vicky Y. Wang
- San Francisco Veterans Affairs Medical Center, San Francisco, CA, United States of America
- Department of Surgery, University of California, San Francisco, CA, United States of America
| | - Ashley E. Morgan
- Department of Surgery, University of California, San Francisco, CA, United States of America
| | - Jiwon Kim
- Department of Medicine, Weill Cornell Medicine, New York, NY, United States of America
| | - Mark D. Handschumacher
- Division of Cardiology, Department of Medicine, Massachusetts General Hospital, Boston, MA, United States of America
| | - Chaya S. Moskowitz
- Department of Epidemiology and Biostatistics, Memorial Sloan Kettering Cancer Center, New York, NY, United States of America
| | - Robert A. Levine
- Division of Cardiology, Department of Medicine, Massachusetts General Hospital, Boston, MA, United States of America
| | - Liang Ge
- San Francisco Veterans Affairs Medical Center, San Francisco, CA, United States of America
- Department of Surgery, University of California, San Francisco, CA, United States of America
| | - Julius M. Guccione
- San Francisco Veterans Affairs Medical Center, San Francisco, CA, United States of America
- Department of Surgery, University of California, San Francisco, CA, United States of America
| | - Jonathan W. Weinsaft
- Department of Medicine, Weill Cornell Medicine, New York, NY, United States of America
| | - Mark B. Ratcliffe
- San Francisco Veterans Affairs Medical Center, San Francisco, CA, United States of America
- Department of Surgery, University of California, San Francisco, CA, United States of America
- * E-mail:
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Morgan AE, Dewey E, Mudd JO, Gelow JM, Davis J, Song HK, Tibayan FA, Bhamidipati CM. The role of estrogen, immune function and aging in heart transplant outcomes. Am J Surg 2019; 218:737-743. [DOI: 10.1016/j.amjsurg.2019.07.007] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2019] [Revised: 05/05/2019] [Accepted: 07/16/2019] [Indexed: 11/24/2022]
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Morgan AE, Wozniak CJ, Gulati S, Ge L, Grossi EA, Weinsaft JW, Ratcliffe MB. Association of Uneven MitraClip Application and Leaflet Stress in a Finite Element Model. JAMA Surg 2018; 152:111-114. [PMID: 27706490 DOI: 10.1001/jamasurg.2016.3360] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Affiliation(s)
| | - Curtis J Wozniak
- Division of Cardiac Surgery, Department of Surgery, University of California, San Francisco, San Francisco3San Francisco VA Medical Center, San Francisco, California
| | - Sarthak Gulati
- Department of Cardiology, University of California, Los Angeles, Los Angeles
| | - Liang Ge
- San Francisco VA Medical Center, San Francisco, California5Departments of Surgery and Bioengineering, University of California, San Francisco
| | - Eugene A Grossi
- Department of Cardiothoracic Surgery, NYU School of Medicine, New York, New York
| | - Jonathan W Weinsaft
- Departments of Medicine (Cardiology) and Radiology, Weill Cornell College of Medicine, New York, New York
| | - Mark B Ratcliffe
- San Francisco VA Medical Center, San Francisco, California8Departments of Surgery and Bioengineering, University of California, San Francisco
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Morgan AE, Zhang Y, Tartibi M, Goldburg S, Kim JJ, Nguyen TD, Guccione J, Ge L, Weinsaft JW, Ratcliffe MB. Ischemic Mitral Regurgitation: Abnormal Strain Overestimates Nonviable Myocardium. Ann Thorac Surg 2018; 105:1754-1761. [PMID: 29391146 DOI: 10.1016/j.athoracsur.2018.01.005] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/25/2017] [Revised: 11/28/2017] [Accepted: 01/03/2018] [Indexed: 12/29/2022]
Abstract
BACKGROUND Therapy for moderate ischemic mitral regurgitation remains unclear. Determination of myocardial viability, a necessary prerequisite for an improvement in regional contractility, is a likely key factor in determining response to revascularization alone. Myocardial strain has been proposed as a viability measure but has not been compared with late gadolinium enhancement (LGE) cardiac magnetic resonance imaging. We hypothesized that abnormal strain overestimates nonviable left ventricular (LV) segments measured with LGE and that ischemia and mechanical tethering by adjacent transmural myocardial infarction (TMI) also decreases strain in viable segments. METHODS Sixteen patients with mild or greater ischemic mitral regurgitation and 7 healthy volunteers underwent cardiac magnetic resonance imaging with noninvasive tags (complementary spatial modulation of magnetization [CSPAMM]), LGE, and stress perfusion. CSPAMM images were post-processed with harmonic phase and circumferential and longitudinal strains were calculated. Viability was defined as the absence of TMI on LGE (hyperenhancement >50% of wall thickness). The borderzone was defined as any segment bordering TMI. Abnormal strain thresholds (±1 to 2.5 SDs from normal mean) were compared with TMI, ischemia, and borderzone. RESULTS 7.4% of LV segments had TMI on LGE, and more than 14.5% of LV segments were nonviable by strain thresholds (p < 0.005). In viable segments, ischemia impaired longitudinal strain (least perfused one-third of LV segments: -0.18 ± 0.08 versus most perfused: -0.22 ± 0.1, p = 0.01) and circumferential strain (-0.12 ± 0.1 versus -0.16 ± 0.08, p < 0.05). In addition, infarct proximity impaired longitudinal strain (-0.16 ± 0.11 borderzone versus -0.18 ± 0.09 remote, p = 0.05). CONCLUSIONS Impaired LV strain overestimates nonviable myocardium compared with TMI on LGE. Ischemia and infarct proximity also decrease strain in viable segments.
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Affiliation(s)
- Ashley E Morgan
- East Bay Surgical Residency, University of California, San Francisco, California
| | - Yue Zhang
- Surgical Service, Veterans Affairs Medical Center, San Francisco, California
| | - Mehrzad Tartibi
- Surgical Service, Veterans Affairs Medical Center, San Francisco, California
| | - Samantha Goldburg
- Department of Medicine (Cardiology), Weill Cornell Medical College, New York, New York
| | - Jiwon J Kim
- Department of Medicine (Cardiology), Weill Cornell Medical College, New York, New York
| | - Thanh D Nguyen
- Department of Radiology, Weill Cornell Medical College, New York, New York
| | - Julius Guccione
- Department of Bioengineering, University of California, San Francisco, California; Surgical Service, Veterans Affairs Medical Center, San Francisco, California; Department of Surgery, University of California, San Francisco, California
| | - Liang Ge
- Department of Bioengineering, University of California, San Francisco, California; Surgical Service, Veterans Affairs Medical Center, San Francisco, California; Department of Surgery, University of California, San Francisco, California
| | - Jonathan W Weinsaft
- Department of Medicine (Cardiology), Weill Cornell Medical College, New York, New York
| | - Mark B Ratcliffe
- Department of Bioengineering, University of California, San Francisco, California; Surgical Service, Veterans Affairs Medical Center, San Francisco, California; Department of Surgery, University of California, San Francisco, California.
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Kim J, Di Franco A, Seoane T, Srinivasan A, Kampaktsis PN, Geevarghese A, Goldburg SR, Khan SA, Szulc M, Ratcliffe MB, Levine RA, Morgan AE, Maddula P, Rozenstrauch M, Shah T, Devereux RB, Weinsaft JW. Right Ventricular Dysfunction Impairs Effort Tolerance Independent of Left Ventricular Function Among Patients Undergoing Exercise Stress Myocardial Perfusion Imaging. Circ Cardiovasc Imaging 2017; 9:CIRCIMAGING.116.005115. [PMID: 27903538 DOI: 10.1161/circimaging.116.005115] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/21/2016] [Accepted: 09/19/2016] [Indexed: 01/20/2023]
Abstract
BACKGROUND Right ventricular (RV) and left ventricular (LV) function are closely linked due to a variety of factors, including common coronary blood supply. Altered LV perfusion holds the potential to affect the RV, but links between LV ischemia and RV performance, and independent impact of RV dysfunction on effort tolerance, are unknown. METHODS AND RESULTS The population comprised 2051 patients who underwent exercise stress myocardial perfusion imaging and echo (5.5±7.9 days), among whom 6% had echo-evidenced RV dysfunction. Global summed stress scores were ≈3-fold higher among patients with RV dysfunction, attributable to increments in inducible and fixed LV perfusion defects (all P≤0.001). Regional inferior and lateral wall ischemia was greater among patients with RV dysfunction (both P<0.01), without difference in corresponding anterior defects (P=0.13). In multivariable analysis, inducible inferior and lateral wall perfusion defects increased the likelihood of RV dysfunction (both P<0.05) independent of LV function, fixed perfusion defects, and pulmonary artery pressure. Patients with RV dysfunction demonstrated lesser effort tolerance whether measured by exercise duration (6.7±2.8 versus 7.9±2.9 minutes; P<0.001) or peak treadmill stage (2.6±0.9 versus 3.1±1.0; P<0.001), paralleling results among patients with LV dysfunction (7.0±2.9 versus 8.0±2.9; P<0.001|2.7±1.0 versus 3.1±1.0; P<0.001 respectively). Exercise time decreased stepwise in relation to both RV and LV dysfunction (P<0.001) and was associated with each parameter independent of age or medication regimen. CONCLUSIONS Among patients with known or suspected coronary artery disease, regional LV ischemia involving the inferior and lateral walls confers increased likelihood of RV dysfunction. RV dysfunction impairs exercise tolerance independent of LV dysfunction.
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Affiliation(s)
- Jiwon Kim
- From the Greenberg Cardiology Division, Department of Medicine (J.K., T.S., A.S., P.N.K., A.G., S.R.G., S.A.K., M.S., P.M., M.R., T.S., R.B.D., J.W.W.) and Department of Cardiothoracic Surgery (A.D.F.), Weill Cornell Medical College, New York, NY; Division of Cardiology, Department of Surgery (M.B.R., A.E.M.), and Department of Bioengineering (M.B.R., A.E.M.), University of California, San Francisco; Veterans Affairs Medical Center, San Francisco, CA (M.B.R., A.E.M.); and Massachusetts General Hospital, Harvard Medical School, Boston (R.A.L.)
| | - Antonino Di Franco
- From the Greenberg Cardiology Division, Department of Medicine (J.K., T.S., A.S., P.N.K., A.G., S.R.G., S.A.K., M.S., P.M., M.R., T.S., R.B.D., J.W.W.) and Department of Cardiothoracic Surgery (A.D.F.), Weill Cornell Medical College, New York, NY; Division of Cardiology, Department of Surgery (M.B.R., A.E.M.), and Department of Bioengineering (M.B.R., A.E.M.), University of California, San Francisco; Veterans Affairs Medical Center, San Francisco, CA (M.B.R., A.E.M.); and Massachusetts General Hospital, Harvard Medical School, Boston (R.A.L.)
| | - Tania Seoane
- From the Greenberg Cardiology Division, Department of Medicine (J.K., T.S., A.S., P.N.K., A.G., S.R.G., S.A.K., M.S., P.M., M.R., T.S., R.B.D., J.W.W.) and Department of Cardiothoracic Surgery (A.D.F.), Weill Cornell Medical College, New York, NY; Division of Cardiology, Department of Surgery (M.B.R., A.E.M.), and Department of Bioengineering (M.B.R., A.E.M.), University of California, San Francisco; Veterans Affairs Medical Center, San Francisco, CA (M.B.R., A.E.M.); and Massachusetts General Hospital, Harvard Medical School, Boston (R.A.L.)
| | - Aparna Srinivasan
- From the Greenberg Cardiology Division, Department of Medicine (J.K., T.S., A.S., P.N.K., A.G., S.R.G., S.A.K., M.S., P.M., M.R., T.S., R.B.D., J.W.W.) and Department of Cardiothoracic Surgery (A.D.F.), Weill Cornell Medical College, New York, NY; Division of Cardiology, Department of Surgery (M.B.R., A.E.M.), and Department of Bioengineering (M.B.R., A.E.M.), University of California, San Francisco; Veterans Affairs Medical Center, San Francisco, CA (M.B.R., A.E.M.); and Massachusetts General Hospital, Harvard Medical School, Boston (R.A.L.)
| | - Polydoros N Kampaktsis
- From the Greenberg Cardiology Division, Department of Medicine (J.K., T.S., A.S., P.N.K., A.G., S.R.G., S.A.K., M.S., P.M., M.R., T.S., R.B.D., J.W.W.) and Department of Cardiothoracic Surgery (A.D.F.), Weill Cornell Medical College, New York, NY; Division of Cardiology, Department of Surgery (M.B.R., A.E.M.), and Department of Bioengineering (M.B.R., A.E.M.), University of California, San Francisco; Veterans Affairs Medical Center, San Francisco, CA (M.B.R., A.E.M.); and Massachusetts General Hospital, Harvard Medical School, Boston (R.A.L.)
| | - Alexi Geevarghese
- From the Greenberg Cardiology Division, Department of Medicine (J.K., T.S., A.S., P.N.K., A.G., S.R.G., S.A.K., M.S., P.M., M.R., T.S., R.B.D., J.W.W.) and Department of Cardiothoracic Surgery (A.D.F.), Weill Cornell Medical College, New York, NY; Division of Cardiology, Department of Surgery (M.B.R., A.E.M.), and Department of Bioengineering (M.B.R., A.E.M.), University of California, San Francisco; Veterans Affairs Medical Center, San Francisco, CA (M.B.R., A.E.M.); and Massachusetts General Hospital, Harvard Medical School, Boston (R.A.L.)
| | - Samantha R Goldburg
- From the Greenberg Cardiology Division, Department of Medicine (J.K., T.S., A.S., P.N.K., A.G., S.R.G., S.A.K., M.S., P.M., M.R., T.S., R.B.D., J.W.W.) and Department of Cardiothoracic Surgery (A.D.F.), Weill Cornell Medical College, New York, NY; Division of Cardiology, Department of Surgery (M.B.R., A.E.M.), and Department of Bioengineering (M.B.R., A.E.M.), University of California, San Francisco; Veterans Affairs Medical Center, San Francisco, CA (M.B.R., A.E.M.); and Massachusetts General Hospital, Harvard Medical School, Boston (R.A.L.)
| | - Saadat A Khan
- From the Greenberg Cardiology Division, Department of Medicine (J.K., T.S., A.S., P.N.K., A.G., S.R.G., S.A.K., M.S., P.M., M.R., T.S., R.B.D., J.W.W.) and Department of Cardiothoracic Surgery (A.D.F.), Weill Cornell Medical College, New York, NY; Division of Cardiology, Department of Surgery (M.B.R., A.E.M.), and Department of Bioengineering (M.B.R., A.E.M.), University of California, San Francisco; Veterans Affairs Medical Center, San Francisco, CA (M.B.R., A.E.M.); and Massachusetts General Hospital, Harvard Medical School, Boston (R.A.L.)
| | - Massimiliano Szulc
- From the Greenberg Cardiology Division, Department of Medicine (J.K., T.S., A.S., P.N.K., A.G., S.R.G., S.A.K., M.S., P.M., M.R., T.S., R.B.D., J.W.W.) and Department of Cardiothoracic Surgery (A.D.F.), Weill Cornell Medical College, New York, NY; Division of Cardiology, Department of Surgery (M.B.R., A.E.M.), and Department of Bioengineering (M.B.R., A.E.M.), University of California, San Francisco; Veterans Affairs Medical Center, San Francisco, CA (M.B.R., A.E.M.); and Massachusetts General Hospital, Harvard Medical School, Boston (R.A.L.)
| | - Mark B Ratcliffe
- From the Greenberg Cardiology Division, Department of Medicine (J.K., T.S., A.S., P.N.K., A.G., S.R.G., S.A.K., M.S., P.M., M.R., T.S., R.B.D., J.W.W.) and Department of Cardiothoracic Surgery (A.D.F.), Weill Cornell Medical College, New York, NY; Division of Cardiology, Department of Surgery (M.B.R., A.E.M.), and Department of Bioengineering (M.B.R., A.E.M.), University of California, San Francisco; Veterans Affairs Medical Center, San Francisco, CA (M.B.R., A.E.M.); and Massachusetts General Hospital, Harvard Medical School, Boston (R.A.L.)
| | - Robert A Levine
- From the Greenberg Cardiology Division, Department of Medicine (J.K., T.S., A.S., P.N.K., A.G., S.R.G., S.A.K., M.S., P.M., M.R., T.S., R.B.D., J.W.W.) and Department of Cardiothoracic Surgery (A.D.F.), Weill Cornell Medical College, New York, NY; Division of Cardiology, Department of Surgery (M.B.R., A.E.M.), and Department of Bioengineering (M.B.R., A.E.M.), University of California, San Francisco; Veterans Affairs Medical Center, San Francisco, CA (M.B.R., A.E.M.); and Massachusetts General Hospital, Harvard Medical School, Boston (R.A.L.)
| | - Ashley E Morgan
- From the Greenberg Cardiology Division, Department of Medicine (J.K., T.S., A.S., P.N.K., A.G., S.R.G., S.A.K., M.S., P.M., M.R., T.S., R.B.D., J.W.W.) and Department of Cardiothoracic Surgery (A.D.F.), Weill Cornell Medical College, New York, NY; Division of Cardiology, Department of Surgery (M.B.R., A.E.M.), and Department of Bioengineering (M.B.R., A.E.M.), University of California, San Francisco; Veterans Affairs Medical Center, San Francisco, CA (M.B.R., A.E.M.); and Massachusetts General Hospital, Harvard Medical School, Boston (R.A.L.)
| | - Pooja Maddula
- From the Greenberg Cardiology Division, Department of Medicine (J.K., T.S., A.S., P.N.K., A.G., S.R.G., S.A.K., M.S., P.M., M.R., T.S., R.B.D., J.W.W.) and Department of Cardiothoracic Surgery (A.D.F.), Weill Cornell Medical College, New York, NY; Division of Cardiology, Department of Surgery (M.B.R., A.E.M.), and Department of Bioengineering (M.B.R., A.E.M.), University of California, San Francisco; Veterans Affairs Medical Center, San Francisco, CA (M.B.R., A.E.M.); and Massachusetts General Hospital, Harvard Medical School, Boston (R.A.L.)
| | - Meenakshi Rozenstrauch
- From the Greenberg Cardiology Division, Department of Medicine (J.K., T.S., A.S., P.N.K., A.G., S.R.G., S.A.K., M.S., P.M., M.R., T.S., R.B.D., J.W.W.) and Department of Cardiothoracic Surgery (A.D.F.), Weill Cornell Medical College, New York, NY; Division of Cardiology, Department of Surgery (M.B.R., A.E.M.), and Department of Bioengineering (M.B.R., A.E.M.), University of California, San Francisco; Veterans Affairs Medical Center, San Francisco, CA (M.B.R., A.E.M.); and Massachusetts General Hospital, Harvard Medical School, Boston (R.A.L.)
| | - Tara Shah
- From the Greenberg Cardiology Division, Department of Medicine (J.K., T.S., A.S., P.N.K., A.G., S.R.G., S.A.K., M.S., P.M., M.R., T.S., R.B.D., J.W.W.) and Department of Cardiothoracic Surgery (A.D.F.), Weill Cornell Medical College, New York, NY; Division of Cardiology, Department of Surgery (M.B.R., A.E.M.), and Department of Bioengineering (M.B.R., A.E.M.), University of California, San Francisco; Veterans Affairs Medical Center, San Francisco, CA (M.B.R., A.E.M.); and Massachusetts General Hospital, Harvard Medical School, Boston (R.A.L.)
| | - Richard B Devereux
- From the Greenberg Cardiology Division, Department of Medicine (J.K., T.S., A.S., P.N.K., A.G., S.R.G., S.A.K., M.S., P.M., M.R., T.S., R.B.D., J.W.W.) and Department of Cardiothoracic Surgery (A.D.F.), Weill Cornell Medical College, New York, NY; Division of Cardiology, Department of Surgery (M.B.R., A.E.M.), and Department of Bioengineering (M.B.R., A.E.M.), University of California, San Francisco; Veterans Affairs Medical Center, San Francisco, CA (M.B.R., A.E.M.); and Massachusetts General Hospital, Harvard Medical School, Boston (R.A.L.)
| | - Jonathan W Weinsaft
- From the Greenberg Cardiology Division, Department of Medicine (J.K., T.S., A.S., P.N.K., A.G., S.R.G., S.A.K., M.S., P.M., M.R., T.S., R.B.D., J.W.W.) and Department of Cardiothoracic Surgery (A.D.F.), Weill Cornell Medical College, New York, NY; Division of Cardiology, Department of Surgery (M.B.R., A.E.M.), and Department of Bioengineering (M.B.R., A.E.M.), University of California, San Francisco; Veterans Affairs Medical Center, San Francisco, CA (M.B.R., A.E.M.); and Massachusetts General Hospital, Harvard Medical School, Boston (R.A.L.).
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Claiborne WCC, Morgan AE, Murina AT. Diffuse Progressive Proliferation of Dark Papules in an Otherwise Healthy African American Woman. JAMA Dermatol 2016; 152:1273-1274. [PMID: 27533288 DOI: 10.1001/jamadermatol.2016.2744] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Affiliation(s)
- W C Cole Claiborne
- Department of Dermatology, Tulane University School of Medicine, New Orleans, Louisiana
| | - Ashley E Morgan
- Tulane University School of Medicine, New Orleans, Louisiana
| | - Andrea Tesvich Murina
- Department of Dermatology, Tulane University School of Medicine, New Orleans, Louisiana
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Pantoja JL, Morgan AE, Grossi EA, Jensen MO, Weinsaft JW, Levine RA, Ge L, Ratcliffe MB. Undersized Mitral Annuloplasty Increases Strain in the Proximal Lateral Left Ventricular Wall. Ann Thorac Surg 2016; 103:820-827. [PMID: 27720201 DOI: 10.1016/j.athoracsur.2016.07.021] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/01/2016] [Revised: 06/10/2016] [Accepted: 07/05/2016] [Indexed: 10/20/2022]
Abstract
BACKGROUND Recurrence of mitral regurgitation (MR) after undersized mitral annuloplasty (MA) for ischemic MR is as high as 60%, with the recurrence rate likely due to continued dilation of the left ventricle (LV). To better understand the causes of recurrent MR, we studied the effect of undersized MA on strain in the LV wall. We hypothesize that the acute change in ventricular shape induced by MA will cause increased strain in regions nearest the mitral valve. METHODS Finite element models were previously reported, based on cardiac magnetic resonance images of 5 sheep with mild to moderate ischemic MR. A 24-mm saddle-shaped rigid annuloplasty ring was modeled and used to simulate virtual MA. Longitudinal and myofiber strains were calculated at end-diastole and end-systole, with preoperative early diastolic geometry as the reference state. RESULTS The undersized MA significantly increased longitudinal strain at end-diastole in the lateral LV wall. The effect was greatest in the proximal-lateral endocardial surface, where longitudinal strain after MA was approximately triple the preoperative strain (11.17% ± 2.15% vs 3.45% ± 0.92%, p = 0.0057). In contrast, postoperative end-diastolic fiber strain decreased in this same region (2.53% ± 2.14% vs 7.72% ± 1.79%, p = 0.0060). There were no significant changes in either strain type at end-systole. CONCLUSIONS Undersized MA increased longitudinal strain in the proximal lateral LV wall at end-diastole. This procedure-related strain at the proximal-lateral LV wall may foster continued LV enlargement and subsequent recurrence of mitral regurgitation.
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Affiliation(s)
- Joe Luis Pantoja
- University of California, San Francisco, San Francisco, California
| | - Ashley E Morgan
- East Bay Surgical Residency, University of California, San Francisco, San Francisco, California
| | - Eugene A Grossi
- Department of Cardiothoracic Surgery, New York University, New York, New York; New York Harbor Veterans Affairs Medical Center, New York, New York
| | - Morten O Jensen
- Department of Biomedical Engineering, University of Arkansas, Fayetteville, Arkansas
| | - Jonathan W Weinsaft
- Departments of Medicine (Cardiology) and Radiology, Weill Cornell Medicine, New York, New York
| | - Robert A Levine
- Division of Cardiology, Department of Medicine, Massachusetts General Hospital, Boston, Massachusetts
| | - Liang Ge
- Department of Surgery, University of California, San Francisco, San Francisco, California; Department of Bioengineering, University of California, San Francisco, San Francisco, California; Veterans Affairs Medical Center, San Francisco, California
| | - Mark B Ratcliffe
- Department of Surgery, University of California, San Francisco, San Francisco, California; Veterans Affairs Medical Center, San Francisco, California.
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Morgan AE, Pantoja JL, Grossi EA, Ge L, Weinsaft JW, Ratcliffe MB. Neochord placement versus triangular resection in mitral valve repair: A finite element model. J Surg Res 2016; 206:98-105. [PMID: 27916382 DOI: 10.1016/j.jss.2016.07.011] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2016] [Revised: 05/23/2016] [Accepted: 07/07/2016] [Indexed: 01/27/2023]
Abstract
BACKGROUND Recurrent mitral regurgitation after mitral valve repair is common, occurring in nearly 50% of patients within 10 years of surgery. Durability of repair is partly related to stress distribution over the mitral leaflets. We hypothesized that repair with neochords (NCs) results in lower stress than leaflet resection (LR). MATERIALS AND METHODS Magnetic resonance imaging and 3D echocardiography were performed before surgical repair of P2 prolapse in a single patient. A finite element model of the left ventricle and mitral valve was created previously, and the modeling program LS-DYNA was used to calculate leaflet stress for the following repairs: Triangular LR; LR with ring annuloplasty (LR + RA); One NC; Two NCs; and 2NC + RA. RESULTS (1) NC placement resulted in stable posterior leaflet stress: Baseline versus 2 NC at end diastole (ED), 12.1 versus 12.0 kPa, at end systole (ES) 20.3 versus 21.7 kPa. (2) In contrast, LR increased posterior leaflet stress: Baseline versus LR at ED 12.1 versus 40.8 kPa, at ES 20.3 versus 46.1 kPa. (3) All repair types reduced anterior leaflet stress: Baseline versus 2 NC versus LR 34.2 versus 25.8 versus 20.6 kPa at ED and 80.8 versus 76.8 versus 67.8 kPa at ES. (4) The addition of RA reduced leaflet stress relative to repair without RA. CONCLUSIONS Neochord repair restored normal leaflet coaptation without creating excessive leaflet stress, whereas leaflet resection more than doubled stress across the posterior leaflet. The excess stress created by leaflet resection was partially, but not completely, mitigated by ring annuloplasty.
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Affiliation(s)
- Ashley E Morgan
- East Bay Surgical Residency, University of California, San Francisco, California
| | - Joe L Pantoja
- College of Medicine, University of California, San Francisco, California
| | - Eugene A Grossi
- Department of Cardiothoracic Surgery, New York University, New York, New York; Department of Cardiothoracic Surgery, New York Harbor Veterans Affairs Medical Center, New York, New York
| | - Liang Ge
- Department of Surgery, University of California, San Francisco, California; Department of Bioengineering, University of California, San Francisco, California; Department of Surgery, Veterans Affairs Medical Center, San Francisco, California
| | - Jonathan W Weinsaft
- Department of Medicine (Cardiology), Weill Cornell Medical College, New York, New York; Department of Radiology, Weill Cornell Medical College, New York, New York
| | - Mark B Ratcliffe
- Department of Surgery, University of California, San Francisco, California; Department of Bioengineering, University of California, San Francisco, California; Department of Surgery, Veterans Affairs Medical Center, San Francisco, California.
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Morgan AE, Pantoja JL, Weinsaft J, Grossi E, Guccione JM, Ge L, Ratcliffe M. Finite Element Modeling of Mitral Valve Repair. J Biomech Eng 2016; 138:021009. [PMID: 26632260 PMCID: PMC5101040 DOI: 10.1115/1.4032125] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [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: 08/15/2015] [Revised: 11/18/2015] [Indexed: 11/08/2022]
Abstract
The mitral valve is a complex structure regulating forward flow of blood between the left atrium and left ventricle (LV). Multiple disease processes can affect its proper function, and when these diseases cause severe mitral regurgitation (MR), optimal treatment is repair of the native valve. The mitral valve (MV) is a dynamic structure with multiple components that have complex interactions. Computational modeling through finite element (FE) analysis is a valuable tool to delineate the biomechanical properties of the mitral valve and understand its diseases and their repairs. In this review, we present an overview of relevant mitral valve diseases, and describe the evolution of FE models of surgical valve repair techniques.
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Affiliation(s)
- Ashley E. Morgan
- University of California,
San Francisco—East Bay Surgical Residency,
Oakland, CA 94602
e-mail:
| | - Joe Luis Pantoja
- School of Medicine,
University of California, San Francisco,
San Francisco, CA 94143
e-mail:
| | - Jonathan Weinsaft
- Department of Cardiology,
Cornell University School of Medicine,
New York, NY 10065
e-mail:
| | - Eugene Grossi
- Department of Cardiothoracic Surgery,
NYU School of Medicine,
New York, NY 10016
e-mail:
| | - Julius M. Guccione
- Department of Surgery and Bioengineering,
University of California, San Francisco,
San Francisco, CA 94143
e-mail:
| | - Liang Ge
- Department of Surgery and Bioengineering,
Veterans Affairs Medical Center,
University of California, San Francisco,
San Francisco, CA 94121
e-mail:
| | - Mark Ratcliffe
- Surgical Service (112)
Departments of Surgery and Bioengineering,
Veterans Affairs Medical Center,
University of California, San Francisco,
4150 Clement Street,
San Francisco, CA 94121
e-mail:
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Morgan AE, Singer-Harris N, Bernstein JH, Waber DP. Characteristics of children referred for evaluation of school difficulties who have adequate academic achievement scores. J Learn Disabil 2000; 33:489-500. [PMID: 15495550 DOI: 10.1177/002221940003300509] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Forty children (7 to 11 years old) referred for evaluation of learning problems, who had scores within the normal range on standardized measures of academic achievement, were compared to 81 similarly referred children who had scored low (< 90) on at least one measure of academic achievement. We tested the hypothesis that children with normal achievement scores who are referred for evaluation of learning problems show neuropsychological profiles comparable to those of children with low achievement. Referral problems, school history, IQ, academic achievement, and neuropsychological function were evaluated. Referred children with normal achievement scores came from more advantaged backgrounds and had less intensive academic interventions, higher IQs, and better decoding skills. Nonetheless, the two groups showed similar neuropsychological profiles. Vulnerability to complexity and decreased automaticity were prominent. Normal-range achievement test scores among children referred for evaluation should not be regarded as indicating absence of neurodevelopmental vulnerability.
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Ashby CR, Rohatgi R, Ngosuwan J, Borda T, Gerasimov MR, Morgan AE, Kushner S, Brodie JD, Dewey SL. Implication of the GABA(B) receptor in gamma vinyl-GABA's inhibition of cocaine-induced increases in nucleus accumbens dopamine. Synapse 1999; 31:151-3. [PMID: 10024012 DOI: 10.1002/(sici)1098-2396(199902)31:2<151::aid-syn8>3.0.co;2-w] [Citation(s) in RCA: 48] [Impact Index Per Article: 1.9] [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: 11/06/2022]
Abstract
Previously, we demonstrated that gamma vinyl-GABA (GVG, Vigabatrin) dose-dependently inhibits cocaine-induced increases in dopamine (DA) concentrations in both the rodent and primate brain. Furthermore, it abolishes cocaine self-administration and conditioned place preference, while having no effect on locomotor activity or drug delivery to the brain. In an effort to better understand the mechanisms underlying this inhibition, we examined the effect of the selective GABA(B) receptor antagonist SCH 50911 on the GVG-induced decrease in cocaine's elevation of extracellular DA concentrations in the nucleus accumbens (NACC). Cocaine administration alone (20 mg/kg i.p.) produced a 480% increase in extracellular NACC DA levels. GVG (300 mg/kg i.p.) significantly reduced this increase by 25% (P<0.01). In sharp contrast, extracellular DA levels increased to 550% after the sequential administration of SCH 50911 (3 mg/kg i.p.), GVG, and cocaine. This increase is significantly different than GVG and cocaine (P<0.05) but similar to cocaine alone. These results demonstrate that the GABA(B) antagonist SCH 50911 was able to completely abolish GVG's inhibition of cocaine-induced increases in DA in the NACC and implicates the GABA(B) receptor in the mechanism underlying this inhibition.
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Affiliation(s)
- C R Ashby
- Department of Pharmaceutical Health Sciences, St. John's University, Jamaica, New York 11439, USA
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Abstract
Cocaine's addictive liability has been linked to its pharmacologic actions on mesotelencephalic dopamine (DA) reinforcement/reward pathways in the central nervous system (CNS). Dopaminergic transmission within these pathways is modulated by gamma-aminobutyric acid (GABA). With this knowledge, we examined the utility of gamma vinylGABA (GVG), a selective and irreversible inhibitor of GABA-transaminase (GABA-T) known to potentiate GABAergic inhibition, to alter cocaine's biochemical effects as well as its effects on behaviors associated with these biochemical changes. GVG significantly attenuated cocaine-induced increases in neostriatal synaptic DA in the non-human primate (baboon) brain as assessed by positron emission tomography (PET) and abolished both the expression and acquisition of cocaine-induced conditioned place preference (CPP). It had no effect on CPP for a food reward, the delivery of cocaine to the brain or locomotor activity. These findings suggest the possible therapeutic utility in cocaine addiction of a pharmacologic strategy targeted at the GABAergic neurotransmitter system, a system distinct from but functionally linked to the DA mesotelencephalic reward/reinforcement system. However, rather than targeting the GABA receptor complex with a direct GABA agonist, this novel approach with GVG takes advantage of the prolonged effects of an irreversible enzyme inhibitor that raises endogenous GABA levels without the addictive liability associated with GABA agonists acting directly at the receptor itself. Human trials with GVG are currently being developed to directly examine the utility of this novel strategy for the treatment of cocaine addiction.
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Affiliation(s)
- S L Dewey
- Chemistry Department, Brookhaven National Laboratory, Upton, NY 11973, USA.
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Morgan AE, Brodie JD, Dewey SL. What are we measuring with PET? Q J Nucl Med 1998; 42:151-7. [PMID: 9796363] [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] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
Abstract
Positron emission tomography is a medical imaging technique that provides unique information concerning many biochemical mechanisms underlying normal physiologic function. With respect to the central nervous system (CNS), selective radiolabeled compounds targeted at specific neurotransmitter receptor systems reveal information not only concerning receptor distribution and enzymatic activity but neurotransmitter concentrations as well. Recent advances in our understanding of these systems may be utilized to further understand changes in brain biochemistry that either result from or produce symptomatology associated with many CNS disease states. The ability to measure interactions between neurotransmitter systems in the human brain may also add to our knowledge of drug side effects and disease progression. While many CNS diseases have been defined as "neurotransmitter-specific" in nature, scientific data now suggests that changes in multiple neurotransmitter systems are evident in the brains of patients suffering from these classically described diseases. PET is a powerful tool that can be used to examine many of these changes in the living human brain.
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Affiliation(s)
- A E Morgan
- Chemistry Department, Brookhaven National Laboratory, Upton, New York 11973, USA
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Abstract
This article addresses the relationship between patterns of planum temporale symmetry/asymmetry and dyslexia and neurolinguistic abilities. Considerable research indicates that dyslexic individuals typically do not display the predominant pattern of leftward planum temporale asymmetry. Variable findings on the structural basis of symmetry are due partially to measurement issues, which are examined in some detail in this critical review. The physiological basis of symmetry may be reduced neuronal elimination in the right planum, although other alternatives are offered. Theories are offered to explain how symmetrical plana are related to dyslexia, and it is evident that symmetrical plana are not sufficient to produce dyslexia. However, some evidence suggests that nonleftward plana asymmetry is associated with deficits in verbal comprehension, phonological decoding, and expressive language. It is concluded that nonleftward asymmetry is associated with linguistic deficits, but that explanatory theories need to be further developed. Among the many issues that need to be addressed, future research needs to determine whether the relationship between patterns of planum temporale symmetry/asymmetry and linguistic ability is specific to dyslexia or if asymmetry covaries lawfully with linguistic abilities in nondyslexic populations.
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Affiliation(s)
- A E Morgan
- Center for Clinical and Development Neuropsychology, University of Georgia, Athens 30602, USA
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Abstract
Cocaine-induced increases in extracellular dopamine (DA) concentrations were measured using in vivo microdialysis techniques in the nucleus accumbens (NACC) of freely moving rats. In control animals, cocaine increased extracellular DA concentrations approximately 482% 60 min following administration, returning to baseline values 200 min later. When administered 2 h following an acute dose of gamma-vinyl-GABA (GVG, Vigabatrin), cocaine-induced increases in extracellular DA were reduced to approximately 365% of baseline values. Chronic GVG administration further dose-dependently attenuated the effects of cocaine but did not alter the rate of increase or the rate of return to baseline values. These results indicate that GVG, a drug that increases brain GABA concentrations, is effective in attenuating the effect of cocaine on NACC DA. Taken with our earlier findings, these results support the targeting of brain GABAergic systems as a potentially effective pharmacologic treatment strategy for cocaine addiction.
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Affiliation(s)
- A E Morgan
- Chemistry Department, Brookhaven National Laboratory, Upton, New York 11973, USA
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Abstract
Using in vivo microdialysis techniques, the effects of RTI-55 and/or cocaine on extracellular dopamine (DA) concentrations were measured in the nucleus accumbens (NACC) of freely moving rats. In control animals, cocaine (20 mg/kg) increased NACC DA approximately 458% 60 minutes following administration, returning to baseline values within 200 minutes. Similarly, RTI-55 administration (0.25 mg/kg) increased NACC DA levels approximately 347%. When combined, however, cocaine further increased NACC DA to 705% of baseline values when given 4 hours following RTI-55. This increase was significantly larger than cocaine alone (P < 0.05). In addition, chronic RTI-55 administration (5 days) further potentiated cocaine's ability to increase NACC DA (783%) but this did not reach statistical significance (P > 0.1) compared to acute RTI55/cocaine animals. These findings indicate that RTI-55, a drug that binds directly to the dopamine transporter (DAT) with higher affinity than cocaine, does not appear to be effective in attenuating cocaine's effects on NACC dopamine levels. In fact, acute RTI-55 potentiates cocaine's effects on NACC DA.
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Affiliation(s)
- A E Morgan
- Chemistry Department, Brookhaven National Laboratory, Upton, New York 11973, USA
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Abstract
This study investigated the role that sensory nerves play in mediating the hormone and glucose metabolic response to endotoxin [lipopolysaccharide (LPS)]. Adult rats were pretreated subcutaneously with capsaicin to selectively destroy primary sensory afferent nerve fibers. Ten days later, [3-3H]glucose was infused intravenously to assess whole body glucose flux before and after the intravenous injection of Escherichia coli LPS (100 micrograms/100 g body wt). Control animals responded to LPS with characteristic increases in the plasma concentration of glucose (91%) and lactate (threefold) and elevations in the rates of glucose appearance and disappearance (77%). In capsaicin-treated rats, the maximal LPS-induced increase in these parameters was attenuated by 50-60%. In addition, these animals were hypoglycemic at the conclusion of the experiment. Control animals demonstrated early and sustained elevations in circulating levels of corticosterone, glucagon, and catecholamines. In contrast, the early LPS-induced elevation in epinephrine and norepinephrine, and to a lesser extent glucagon, was completely absent or greatly impaired by capsaicin pretreatment. In a separate study, the epinephrine-induced increase in glucose flux was blunted by 75% in capsaicin-treated rats. These data indicate that sensory afferent neurons play a critical role in the early secretory response of glucagon and catecholamines, the maintenance of tissue catecholamine responsiveness, and the stimulation of glucose production after LPS.
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Affiliation(s)
- A E Morgan
- Department of Surgery, State University of New York at Stony Brook 11794-8191, USA
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Morgan AE, Horan B, Dewey SL, Ashby CR. Repeated administration of 3,4-methylenedioxymethamphetamine augments cocaine's action on dopamine in the nucleus accumbens: a microdialysis study. Eur J Pharmacol 1997; 331:R1-3. [PMID: 9274936 DOI: 10.1016/s0014-2999(97)01035-2] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.3] [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: 02/05/2023]
Abstract
In this study, we examined the ability of a single injection of cocaine (20 mg/kg, i.p.) to augment extracellular dopamine levels in the nucleus accumbens two weeks after pretreating rats with either saline (1 ml/kg, i.p.) or the serotonin neurotoxin 3,4-methylenedioxymethamphetamine (20 mg/kg, s.c., twice daily for 4 days). The level of dopamine in the nucleus accumbens was measured using in vivo microdialysis. Cocaine produced a 400% increase in extracellular nucleus accumbens dopamine levels in control rats, whereas in 3,4-methylenedioxymethamphetamine treated rats the increase produced by cocaine was 800%, which was significantly different from controls. This suggests that 3,4-methylenedioxymethamphetamine, a relatively common drug of abuse, may alter subsequent vulnerability to cocaine dependence and abuse.
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Affiliation(s)
- A E Morgan
- Chemistry Department, Brookhaven National Laboratory, Upton, NY 11973, USA
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Morgan AE, Hynd GW, Riccio CA, Hall J. Validity of DSM-IV ADHD predominantly inattentive and combined types: relationship to previous DSM diagnoses/subtype differences. J Am Acad Child Adolesc Psychiatry 1996; 35:325-33. [PMID: 8714321 DOI: 10.1097/00004583-199603000-00014] [Citation(s) in RCA: 119] [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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
UNLABELLED Since 1980, three different diagnostic nomenclatures have been published regarding attention-deficit hyperactivity disorder (ADHD). These changing conceptualizations and diagnostic criteria have generated considerable confusion. OBJECTIVE To examine the multidimensional DSM-IV ADHD criteria in relation to how children and adolescents with a previous DSM-III ADD diagnosis or a DSM-III-R ADHD diagnosis are diagnosed according to DSM-IV criteria. METHOD Children whose original diagnoses were according to DSM-III and DSM-III-R criteria received retrospective diagnoses according to DSM-IV criteria. RESULTS Predominantly inattentive (n = 30) and combined types (n = 26) were compared on their previous DSM-III and DSM-III-R diagnoses and on demographic, behavioral, cognitive, and comorbidity variables. Predominantly inattentive and combined type diagnoses corresponded with DSM-III ADD/WO and ADD/H diagnoses, respectively. The DSM-III-R ADHD diagnosis did not correspond with either DSM-IV subtype. Children with the combined type diagnosis had more externalizing codiagnoses, and their parents reported more externalizing, delinquent, and aggressive behaviors. Children with the predominantly inattentive type had more math learning disability codiagnoses. CONCLUSION Results support a multidimensional conceptualization of ADHD. There exists close correspondence between the DSM-III ADD/WO type and the DSM-IV predominantly inattentive type and between the DSM-III ADD/H type and the DSM-IV combined type.
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Affiliation(s)
- A E Morgan
- University of Georgia, Athens 30602, USA
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Abstract
The purpose of this study is to describe patterns of pain, analgesic use, barriers to pain control, and various aspects of lifestyle affected by pain in hospice patients. Seventy-six charts of deceased patients were randomly selected of patients who had received care from Hospice of Wake County between August 1990 and August 1991. All patient's charts were reviewed from date of entry into hospice until death. Pain assessments were routinely performed at entry into hospice, then at one month intervals, and, thereafter, whenever a change in pain status occurred. The average number of pain assessments performed per patient was 2.7 (range 18). Pain intensity score increased as the number of pain assessments increased. Pain was described as occasional (25.2 percent), frequent (26.6 percent) or constant (24.1 percent). Most common analgesic medications were long-acting morphine sulphate (25.4 percent), acetaminophen and hydroxy/oxycodone combinations (20.1 percent) and NSAIDS (17.1 percent). Approximately 40 percent of all pain assessments reflected use of greater than one analgesic agent and prn and scheduled medications simultaneously. Eighty percent of all pain assessments prompted a recommendation to change the analgesic regimen and 62.5 percent of regimen changes were associated with improvement in pain status. Barriers to pain control and lifestyle alterations due to pain were identified. The positive findings in this report, compared to previous similar investigations, supports the use of the pain assessment document and guidelines for cancer pain management in use at the Hospice of Wake County.
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Walsh TA, Morgan AE, Hey TD. Characterization and molecular cloning of a proenzyme form of a ribosome-inactivating protein from maize. Novel mechanism of proenzyme activation by proteolytic removal of a 2.8-kilodalton internal peptide segment. J Biol Chem 1991; 266:23422-7. [PMID: 1744135] [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: 12/28/2022] Open
Abstract
Ribosome-inactivating proteins (RIPs) are a widely distributed family of plant enzymes that are remarkably potent catalytic inactivators of eukaryotic protein synthesis. All RIPs described to date, including the A-chain of the plant cytotoxin ricin, are polypeptides of 25-32 kDa and share significant amino acid sequence homologies. We have characterized and cloned an RIP from maize (Zea mays). In contrast to previously described RIPs, we have found that maize RIP is synthesized and stored in the kernel as a 34-kDa inactive precursor (isoelectric point = 6.5). During germination, this neutral precursor is converted into a basic, active form (isoelectric point greater than 9) by limited proteolysis, which removes 25 amino acids (2.8 kDa) of net charge -6 from the center of the polypeptide chain. Additional processing also occurs at the amino and carboxyl termini of the polypeptide. The sequence of the internal processed region is unique and it is equivalent to an insertion centered around Thr-156 in the amino acid sequence of ricin toxin A-chain, i.e. in the center of the enzymatically active domain. The generation of an active enzyme by removal of a large amino acid segment from the middle of a precursor polypeptide chain represents a novel mechanism of proenzyme activation that is distinct from more conventional activation mechanisms involving NH2-terminal proteolytic processing. A two-chain active RIP (comprised of 16.5- and 8.5-kDa fragments that remain tightly associated) is produced from this processing event.
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Affiliation(s)
- T A Walsh
- Agricultural Biotechnology Laboratory, DowElanco, Midland, Michigan 48674
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