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Cabral S, Restrepo D, Kanjee Z, Wilson P, Crowe B, Abdulnour RE, Rodman A. Clinical Reasoning of a Generative Artificial Intelligence Model Compared With Physicians. JAMA Intern Med 2024; 184:581-583. [PMID: 38557971 PMCID: PMC10985627 DOI: 10.1001/jamainternmed.2024.0295] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/08/2023] [Accepted: 01/16/2024] [Indexed: 04/04/2024]
Abstract
This cross-sectional study assesses the ability of a large language model to process medical data and display clinical reasoning compared with the ability of attending physicians and residents.
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Affiliation(s)
- Stephanie Cabral
- Department of Medicine, Beth Israel Deaconess Medical Center, Boston, Massachusetts
| | - Daniel Restrepo
- Department of Medicine, Massachusetts General Hospital, Boston
| | - Zahir Kanjee
- Department of Medicine, Beth Israel Deaconess Medical Center, Boston, Massachusetts
| | - Philip Wilson
- Department of Medicine, Beth Israel Deaconess Medical Center, Boston, Massachusetts
| | - Byron Crowe
- Department of Medicine, Beth Israel Deaconess Medical Center, Boston, Massachusetts
| | - Raja-Elie Abdulnour
- Department of Pulmonary and Critical Care, Brigham and Women’s Hospital, Boston, Massachusetts
| | - Adam Rodman
- Department of Medicine, Beth Israel Deaconess Medical Center, Boston, Massachusetts
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Restrepo D, Rodman A, Abdulnour RE. Conversations on reasoning: Large language models in diagnosis. J Hosp Med 2024. [PMID: 38678438 DOI: 10.1002/jhm.13378] [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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/08/2024] [Accepted: 04/11/2024] [Indexed: 04/30/2024]
Affiliation(s)
- Daniel Restrepo
- Department of Medicine, Massachusetts General Hospital, Boston, Massachusetts, USA
- Harvard Medical School, Boston, Massachusetts, USA
| | - Adam Rodman
- Harvard Medical School, Boston, Massachusetts, USA
- Department of Medicine, Beth Israel Deaconess Medical Center, Boston, Massachusetts, USA
| | - Raja-Elie Abdulnour
- Harvard Medical School, Boston, Massachusetts, USA
- Department of Medicine, Brigham and Women's Hospital, Boston, Massachusetts, USA
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Siglin J, Restrepo D. A Break in the Case: an Exercise in Clinical Reasoning. J Gen Intern Med 2024:10.1007/s11606-023-08572-y. [PMID: 38499722 DOI: 10.1007/s11606-023-08572-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/25/2023] [Accepted: 12/05/2023] [Indexed: 03/20/2024]
Affiliation(s)
- Jonathan Siglin
- Department of Medicine, Massachusetts General Hospital, 55 Fruit St, Gray 730, Boston, MA, 02114, USA.
| | - Daniel Restrepo
- Department of Medicine, Massachusetts General Hospital, 55 Fruit St, Gray 730, Boston, MA, 02114, USA
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Kashou AH, Noseworthy PA, Beckman TJ, Anavekar NS, Cullen MW, Angstman KB, Sandefur BJ, Shapiro BP, Wiley BW, Kates AM, Sadhu J, Thakker P, Huneycutt D, Braisted A, Smith SW, Baranchuk A, Grauer K, O'Brien K, Kaul V, Gambhir HS, Knohl SJ, Restrepo D, May AM. EDUCATE: An international, randomized controlled trial for teaching electrocardiography. Curr Probl Cardiol 2024; 49:102409. [PMID: 38232918 PMCID: PMC10922800 DOI: 10.1016/j.cpcardiol.2024.102409] [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: 01/14/2024] [Accepted: 01/14/2024] [Indexed: 01/19/2024]
Abstract
INTRODUCTION Despite the critical role of electrocardiograms (ECGs) in patient care, evident gaps exist in ECG interpretation competency among healthcare professionals across various medical disciplines and training levels. Currently, no practical, evidence-based, and easily accessible ECG learning solution is available for healthcare professionals. The aim of this study was to assess the effectiveness of web-based, learner-directed interventions in improving ECG interpretation skills in a diverse group of healthcare professionals. METHODS In an international, prospective, randomized controlled trial, 1206 healthcare professionals from various disciplines and training levels were enrolled. They underwent a pre-intervention test featuring 30 12-lead ECGs with common urgent and non-urgent findings. Participants were randomly assigned to four groups: (i) practice ECG interpretation question bank (question bank), (ii) lecture-based learning resource (lectures), (iii) hybrid question- and lecture-based learning resource (hybrid), or (iv) no ECG learning resources (control). After four months, a post-intervention test was administered. The primary outcome was the overall change in ECG interpretation performance, with secondary outcomes including changes in interpretation time, self-reported confidence, and accuracy for specific ECG findings. Both unadjusted and adjusted scores were used for performance assessment. RESULTS Among 1206 participants, 863 (72 %) completed the trial. Following the intervention, the question bank, lectures, and hybrid intervention groups each exhibited significant improvements, with average unadjusted score increases of 11.4 % (95 % CI, 9.1 to 13.7; P<0.01), 9.8 % (95 % CI, 7.8 to 11.9; P<0.01), and 11.0 % (95 % CI, 9.2 to 12.9; P<0.01), respectively. In contrast, the control group demonstrated a non-significant improvement of 0.8 % (95 % CI, -1.2 to 2.8; P=0.54). While no differences were observed among intervention groups, all outperformed the control group significantly (P<0.01). Intervention groups also excelled in adjusted scores, confidence, and proficiency for specific ECG findings. CONCLUSION Web-based, self-directed interventions markedly enhanced ECG interpretation skills across a diverse range of healthcare professionals, providing an accessible and evidence-based solution.
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Affiliation(s)
- Anthony H Kashou
- Department of Cardiovascular Medicine, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA.
| | - Peter A Noseworthy
- Department of Cardiovascular Medicine, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA
| | - Thomas J Beckman
- Department of Cardiovascular Medicine, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA
| | - Nandan S Anavekar
- Department of Cardiovascular Medicine, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA
| | - Michael W Cullen
- Department of Cardiovascular Medicine, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA
| | - Kurt B Angstman
- Department of Cardiovascular Medicine, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA
| | - Benjamin J Sandefur
- Department of Cardiovascular Medicine, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA
| | | | - Brandon W Wiley
- Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
| | - Andrew M Kates
- Washington University School of Medicine in St. Louis, St. Louis, MO, USA
| | - Justin Sadhu
- Washington University School of Medicine in St. Louis, St. Louis, MO, USA
| | - Prashanth Thakker
- Washington University School of Medicine in St. Louis, St. Louis, MO, USA
| | | | | | - Stephen W Smith
- Hennepin County Medical Center and University of Minnesota, Minneapolis, MN, USA
| | | | - Ken Grauer
- University of Florida, Gainesville, FL, USA
| | | | - Viren Kaul
- SUNY Upstate Medical University, Syracuse, NY, USA
| | | | | | - Daniel Restrepo
- Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Adam M May
- Washington University School of Medicine in St. Louis, St. Louis, MO, USA
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Ma M, Simoes de Souza F, Futia G, Anderson S, Riguero J, Tollin D, Gentile-Polese A, Platt J, Hiratani N, Gibson EA, Restrepo D. Decision-Making Time Cells in Hippocampal Dorsal CA1. bioRxiv 2023:2023.10.01.560382. [PMID: 37873178 PMCID: PMC10592611 DOI: 10.1101/2023.10.01.560382] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/25/2023]
Abstract
Sequential neural dynamics encoded by "time cells" play a crucial role in hippocampal function. However, the role of hippocampal sequential neural dynamics in associative learning is an open question. In this manuscript, we used two-photon Ca2+ imaging of dorsal CA1 pyramidal neurons in head-fixed mice performing a go-no-go associative learning task. We found that pyramidal cells responded differentially to the rewarded or unrewarded stimuli. The stimuli were decoded accurately from the activity of the neuronal ensemble, and accuracy increased substantially as the animal learned to differentiate the stimuli. Decoding the stimulus from individual pyramidal cells that responded differentially revealed that decision-making took place at discrete times after stimulus presentation. Lick prediction decoded from the ensemble activity of cells in dCA1 correlated linearly with lick behavior indicating that sequential activity of pyramidal cells in dCA1 constitutes a temporal memory map used for decision-making in associative learning.
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Affiliation(s)
- M. Ma
- Department of Cell and Developmental Biology, University of Colorado Anschutz Medical Campus, Aurora, CO, 80045, USA
- These authors contributed equally to this work
| | - F. Simoes de Souza
- Department of Cell and Developmental Biology, University of Colorado Anschutz Medical Campus, Aurora, CO, 80045, USA
- Center for Mathematics, Computation and Cognition, Federal University of ABC, Sao Bernardo do Campo, SP, Brazil
- These authors contributed equally to this work
| | - G.L. Futia
- Department of Bioengineering, University of Colorado Anschutz Medical Campus, Aurora, CO, 80045, USA
| | - S.R. Anderson
- Department of Physiology and Biophysics, University of Colorado Anschutz Medical Campus, Aurora, CO, 80045, USA
| | - J. Riguero
- Department of Physiology and Biophysics, University of Colorado Anschutz Medical Campus, Aurora, CO, 80045, USA
- Neuroscience Graduate Program, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - D. Tollin
- Department of Physiology and Biophysics, University of Colorado Anschutz Medical Campus, Aurora, CO, 80045, USA
- Neuroscience Graduate Program, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - A. Gentile-Polese
- Department of Cell and Developmental Biology, University of Colorado Anschutz Medical Campus, Aurora, CO, 80045, USA
| | - J.P. Platt
- Department of Neurosurgery, University of Colorado Anschutz Medical Campus, Aurora, CO, 80045, USA
| | - N. Hiratani
- Department of Neuroscience, Washington University, St. Louis, MO 63110, USA
| | - E. A. Gibson
- Department of Bioengineering, University of Colorado Anschutz Medical Campus, Aurora, CO, 80045, USA
- Neuroscience Graduate Program, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - D. Restrepo
- Department of Cell and Developmental Biology, University of Colorado Anschutz Medical Campus, Aurora, CO, 80045, USA
- Neuroscience Graduate Program, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
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Kashou AH, Noseworthy PA, Beckman TJ, Anavekar NS, Cullen MW, Angstman KB, Sandefur BJ, Thompson CA, Halvorsen AJ, Shapiro BP, Wiley BW, Kates AM, Cosco D, Sadhu JS, Thakker PD, Huneycutt D, Braisted A, Smith SW, Baranchuk A, Grauer K, O'Brien K, Kaul V, Gambhir HS, Knohl SJ, Restrepo D, Kligfield PD, Macfarlane PW, Drew BJ, May AM. Education curriculum assessment for teaching electrocardiography: Rationale and design for the prospective, international, randomized controlled EDUCATE trial. J Electrocardiol 2023; 80:166-173. [PMID: 37467573 DOI: 10.1016/j.jelectrocard.2023.07.005] [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: 05/15/2023] [Revised: 06/20/2023] [Accepted: 07/11/2023] [Indexed: 07/21/2023]
Abstract
BACKGROUND Electrocardiogram (ECG) interpretation training is a fundamental component of medical education across disciplines. However, the skill of interpreting ECGs is not universal among medical graduates, and numerous barriers and challenges exist in medical training and clinical practice. An evidence-based and widely accessible learning solution is needed. DESIGN The EDUcation Curriculum Assessment for Teaching Electrocardiography (EDUCATE) Trial is a prospective, international, investigator-initiated, open-label, randomized controlled trial designed to determine the efficacy of self-directed and active-learning approaches of a web-based educational platform for improving ECG interpretation proficiency. Target enrollment is 1000 medical professionals from a variety of medical disciplines and training levels. Participants will complete a pre-intervention baseline survey and an ECG interpretation proficiency test. After completion, participants will be randomized into one of four groups in a 1:1:1:1 fashion: (i) an online, question-based learning resource, (ii) an online, lecture-based learning resource, (iii) an online, hybrid question- and lecture-based learning resource, or (iv) a control group with no ECG learning resources. The primary endpoint will be the change in overall ECG interpretation performance according to pre- and post-intervention tests, and it will be measured within and compared between medical professional groups. Secondary endpoints will include changes in ECG interpretation time, self-reported confidence, and interpretation accuracy for specific ECG findings. CONCLUSIONS The EDUCATE Trial is a pioneering initiative aiming to establish a practical, widely available, evidence-based solution to enhance ECG interpretation proficiency among medical professionals. Through its innovative study design, it tackles the currently unaddressed challenges of ECG interpretation education in the modern era. The trial seeks to pinpoint performance gaps across medical professions, compare the effectiveness of different web-based ECG content delivery methods, and create initial evidence for competency-based standards. If successful, the EDUCATE Trial will represent a significant stride towards data-driven solutions for improving ECG interpretation skills in the medical community.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | | | - Brandon W Wiley
- Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
| | - Andrew M Kates
- Washington University School of Medicine in St. Louis, St. Louis, MO, USA
| | - Dominique Cosco
- Washington University School of Medicine in St. Louis, St. Louis, MO, USA
| | - Justin S Sadhu
- Washington University School of Medicine in St. Louis, St. Louis, MO, USA
| | | | | | | | - Stephen W Smith
- Hennepin County Medical Center and University of Minnesota, Minneapolis, MN, USA
| | | | - Ken Grauer
- University of Florida, Gainesville, FL, USA
| | | | - Viren Kaul
- SUNY Upstate Medical University, Syracuse, NY, USA
| | | | | | - Daniel Restrepo
- Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Paul D Kligfield
- New York-Presbyterian/Weill Cornell Medical Center, New York, NY, USA
| | | | | | - Adam M May
- Washington University School of Medicine in St. Louis, St. Louis, MO, USA
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Abstract
Point of Care Ultrasound (POCUS) is a growing diagnostic modality across a variety of specialties and is increasingly being taught in undergraduate medical education. Uptake within internal medicine has been slow but is becoming more commonplace. Training of extant hospital medicine faculty, including senior members, in POCUS is an unmet need in graduate medical education with significant pedagogical and patient safety implications. With this in mind, we created a training program for the core teaching faculty at our academic internal medicine residency program. The experiential, hands-on curriculum explored the reasoning behind concepts and emphasized psychological safety for senior faculty learners and was successful and well-received. In our piece, we aim to explore the existing literature around training this unique population in POCUS and report on our single-center experience. We also provide a framework for how our program succeeded, collate tips derived from the expert ultrasound teachers and list pearls learned while teaching these experienced educators. Although this worthwhile effort requires planning and support, it was appreciated even by senior faculty.
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Affiliation(s)
- Daniel Restrepo
- Department of Medicine, Massachusetts General HospitalBoston, MAUSA
- Harvard Medical SchoolBoston, MA
| | - Thomas F Heyne
- Department of Medicine, Massachusetts General HospitalBoston, MAUSA
- Harvard Medical SchoolBoston, MA
| | - Christine Schutzer
- Point-of-Care Ultrasound Program, Oregon Health & Science UniversityPortland, OR
| | - Renee Dversdal
- Point-of-Care Ultrasound Program, Oregon Health & Science UniversityPortland, OR
- Division of Hospital Medicine, Oregon Health & Science UniversityPortland, OR
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Biggerstaff S, Thompson R, Restrepo D. POCUS at home: Point-of-care ultrasound for the home hospitalist. J Hosp Med 2023; 18:87-89. [PMID: 36031731 DOI: 10.1002/jhm.12949] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/24/2022] [Revised: 07/01/2022] [Accepted: 08/05/2022] [Indexed: 01/05/2023]
Affiliation(s)
- Scott Biggerstaff
- Department of General Internal Medicine and Geriatrics, Oregon Health and Science University, Portland, Oregon, USA
| | - Ryan Thompson
- Department of Medicine, Massachusetts General Hospital, Boston, Massachusetts, USA
| | - Daniel Restrepo
- Department of Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts, USA
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Restrepo D, Haramati A, McCluskey SM, Branda JA. Case 22-2022: A 34-Year-Old Woman with Cavitary Lung Lesions. N Engl J Med 2022; 387:261-269. [PMID: 35857663 DOI: 10.1056/nejmcpc2201238] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Affiliation(s)
- Daniel Restrepo
- From the Departments of Medicine (D.R., S.M.M.), Radiology (A.H.), and Pathology (J.A.B.), Massachusetts General Hospital, and the Departments of Medicine (D.R., S.M.M.), Radiology (A.H.), and Pathology (J.A.B.), Harvard Medical School - both in Boston
| | - Adina Haramati
- From the Departments of Medicine (D.R., S.M.M.), Radiology (A.H.), and Pathology (J.A.B.), Massachusetts General Hospital, and the Departments of Medicine (D.R., S.M.M.), Radiology (A.H.), and Pathology (J.A.B.), Harvard Medical School - both in Boston
| | - Suzanne M McCluskey
- From the Departments of Medicine (D.R., S.M.M.), Radiology (A.H.), and Pathology (J.A.B.), Massachusetts General Hospital, and the Departments of Medicine (D.R., S.M.M.), Radiology (A.H.), and Pathology (J.A.B.), Harvard Medical School - both in Boston
| | - John A Branda
- From the Departments of Medicine (D.R., S.M.M.), Radiology (A.H.), and Pathology (J.A.B.), Massachusetts General Hospital, and the Departments of Medicine (D.R., S.M.M.), Radiology (A.H.), and Pathology (J.A.B.), Harvard Medical School - both in Boston
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Gallo-Villegas J, Restrepo D, Pérez L, Castro-Valencia LA, Narvaez-Sanchez R, Osorio J, Aguirre-Acevedo DC, Calderón JC. Safety of High-Intensity, Low-Volume Interval Training or Continuous Aerobic Training in Adults With Metabolic Syndrome. J Patient Saf 2022; 18:295-301. [PMID: 34870388 DOI: 10.1097/pts.0000000000000922] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [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: 11/26/2022]
Abstract
OBJECTIVE The aim of the study was to evaluate the safety of high-intensity, low-volume interval training (HIIT-low volume) compared with moderate-intensity continuous aerobic training (MICT) in adults with metabolic syndrome. METHODS This is a controlled, randomized, clinical trial in patients without history of ischemic heart disease or diabetes, who underwent a supervised, 3 sessions/week, 12-week treadmill exercise program. The HIIT-low volume (n = 29) sessions consisted of 6 intervals with 1-minute, high-intensity phases at 90% of peak oxygen consumption (VO2peak). The MICT (n = 31) trained at 60% of VO2peak for 30 minutes. A new approach to record and classify all clinical events according to possible causality based on Naranjo's algorithm was developed. RESULTS Patients were 50.8 ± 6.0 years old, 70% women, with body mass index of 30.6 ± 4.0 kg/m2 and VO2peak of 29.0 ± 6.3 mL·kg-1·min-1. In total, 60 clinical events were recorded in the HIIT-low volume group and 48 in the MICT group, with 59.3% classified as general disease. Only 21 events were classified as adverse reactions possibly related to exercise, without any serious adverse reactions. Both interventions had a similar incidence of musculoskeletal events (incidence rate ratio, 1.1; 95% confidence interval, 0.6-1.8), but HIIT-low volume had a higher incidence of cardiovascular events (incidence rate ratio, 2.9; 95% CI, 0.4-22.8) after adjusting for age, sex, and body mass index (HIIT-low volume: chest pain [n = 1] and symptoms of venous insufficiency of lower limbs [n = 2]; MICT: chest pain [n = 1]). CONCLUSIONS The HIIT-low volume and MICT are safe in patients with metabolic syndrome. We recommend a muscle-conditioning program prior to both and to avoid HIIT-low volume in treadmill in patients with venous insufficiency of the lower limbs.Trial registration number NCT03087721.
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Affiliation(s)
| | | | | | | | | | | | | | - Juan C Calderón
- Physiology and Biochemistry Research Group-PHYSIS, University of Antioquia
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Vasquez D, Mejia-Mejia E, Torres R, Restrepo D. Perceived stress and physiological consistency during mental stress exercises and controlled breathing. Eur Psychiatry 2022. [PMCID: PMC9567391 DOI: 10.1192/j.eurpsy.2022.1895] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/04/2022] Open
Abstract
Introduction The measurement of the physiological coherence, the order and the quality of the connection of complex systems such as the cardiac and the respiratory system, varies in situations of stress and relaxation. Objectives We aim to assess changes in physiological coherence and perception of stress during mental stress and directed breathing exercises. Methods Repeated-measures study in healthy adults without prior training in breathing techniques, aged between 18 and 65 years of both sexes who were evaluated in three situations: baseline, mental stress (Stroop test and successive subtractions), and directed breathing, during which were captured heart rate and respiratory signals to estimate physiological coherence and the participants rated the perceived stress at each moment. Results 34 participants were analyzed, 59% women, with a median age of 36 years (Rq = 13). During mental stress tasks, the median for physiological coherence was similar to baseline coherence but increased significantly with five minutes of directed breathing exercises (38% vs. 63% p <0.0001). The highest perception of stress was during successive subtractions (Me 7, Rq = 4) and the lowest during directed breathing exercises (Me 2 Rq = 3.0). The correlation was sought between physiological coherence and perception of stress during each of the four moments of the study. Basal (Rho Spearman -0.05, p 0.54); Stroop (Rho -0.17, p 0.03); successive subtractions (Rho 0.50, p 0.77); and directed breathing (Rho -0.28, p 0.09). Conclusions A correlation was found between physiological coherence and perception of stress during the Stroop test; however, no association was found. Disclosure No significant relationships.
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Toro M, Cardona A, Restrepo D, Buitrago L. Does vaporized hydrogen peroxide sterilization affect the geometrical properties of anatomic models and guides 3D printed from computed tomography images? 3D Print Med 2021; 7:29. [PMID: 34519898 PMCID: PMC8439001 DOI: 10.1186/s41205-021-00120-w] [Citation(s) in RCA: 3] [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] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2020] [Accepted: 08/19/2021] [Indexed: 11/18/2022] Open
Abstract
Background Material extrusion is used to 3D print anatomic models and guides. Sterilization is required if a 3D printed part touches the patient during an intervention. Vaporized Hydrogen Peroxide (VHP) is one method of sterilization. There are four factors to consider when sterilizing an anatomic model or guide: sterility, biocompatibility, mechanical properties, and geometric fidelity. This project focuses on geometric fidelity for material extrusion of one polymer acrylonitrile butadiene styrene (ABS) using VHP. Methods De-identified computed tomography (CT) image data from 16 patients was segmented using Mimics Innovation Suite (Materialise NV, Leuven, Belgium). Eight patients had maxillary and mandibular defects depicted with the anatomic models, and eight had mandibular defects for the anatomic guides. Anatomic models and guides designed from the surfaces of CT scan reconstruction and segementation were 3D printed in medical-grade acrylonitrile butadiene styrene (ABS) material extrusion. The 16 parts underwent low-temperature sterilization with VHP. The dimensional error was estimated after sterilization by comparing scanned images of the 3D printed parts. Results The average of the estimated mean differences between the printed pieces before and after sterilization were − 0,011 ± 0,252 mm (95%CI − 0,011; − 0,010) for the models and 0,003 ± 0,057 mm (95%CI 0,002; 0,003) for the guides. Regarding the dimensional error of the sterilized parts compared to the original design, the estimated mean differences were − 0,082 ± 0,626 mm (95%CI − 0,083; − 0,081) for the models and 0,126 ± 0,205 mm (95%CI 0,126, 0,127) for the guides. Conclusion This project tested and verified dimensional stability, one of the four prerequisites for introducing vaporized hydrogen peroxide into 3D printing of anatomic models and guides; the 3D printed parts maintained dimensional stability after sterilization.
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Affiliation(s)
- Mauricio Toro
- TECHFIT Digital Surgery, Industrias Médicas Sampedro, Carrera 47 N° 100 Sur 40 Centro Industrial Portal del Sur, Bodega 14, variante a Caldas, La Estrella (Medellin), Colombia
| | - Aura Cardona
- R&D Department, TECHFIT Digital Surgery, Industrias Médicas Sampedro, La Estrella, Colombia
| | - Daniel Restrepo
- R&D Department, TECHFIT Digital Surgery, Industrias Médicas Sampedro, La Estrella, Colombia
| | - Laura Buitrago
- TECHFIT Digital Surgery, Industrias Médicas Sampedro, Carrera 47 N° 100 Sur 40 Centro Industrial Portal del Sur, Bodega 14, variante a Caldas, La Estrella (Medellin), Colombia.
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Affiliation(s)
- Daniel Restrepo
- Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts (D.R.)
| | - Katrina A Armstrong
- Massachusetts General Hospital and Harvard Medical School; Boston, Massachusetts (K.A.A., J.P.M.)
| | - Joshua P Metlay
- Massachusetts General Hospital and Harvard Medical School; Boston, Massachusetts (K.A.A., J.P.M.)
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Petro JL, Pérez L, Restrepo D, Aguirre-Acevedo D, Trillos C, Yepes-Calderón M, Valbuena L, Sánchez YL, Aristizábal JC, Narvaez-Sanchez R, Calderón JC, Gallo-Villegas J. High-intensity Interval Low-volume Vs Moderate-intensity Continuous Training On Exercise Enjoyment And Quality-of-life In Metabolic Syndrome. Med Sci Sports Exerc 2020. [DOI: 10.1249/01.mss.0000678732.71602.0b] [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: 11/21/2022]
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15
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Gallo-Villegas J, Aguirre-Acevedo D, Pérez L, Restrepo D, Valbuena L, Narváez-Sánchez R, Calderón JC. Safety Of High-intensity Interval Training Low-volume Vs Moderate Intensity Continuous Aerobic Training In Metabolic Syndrome. Med Sci Sports Exerc 2020. [DOI: 10.1249/01.mss.0000678788.53235.53] [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: 11/21/2022]
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Affiliation(s)
- Daniel Restrepo
- Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts (D.R., K.A.A., J.P.M.)
| | - Katrina A Armstrong
- Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts (D.R., K.A.A., J.P.M.)
| | - Joshua P Metlay
- Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts (D.R., K.A.A., J.P.M.)
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Mendez S, Mihatov N, Wing JR, Restrepo D, Vyas JM, Dudzinski DM. UTILIZING AN INTERNAL MEDICINE RESIDENCY PROGRAM NEEDS ASSESSMENT TO FACILITATE A PILOT POINT-OF-CARE ULTRASOUND (POCUS) CURRICULUM. J Am Coll Cardiol 2020. [DOI: 10.1016/s0735-1097(20)34140-1] [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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Abstract
We present the case of a 47-year-old man with a history of diabetes mellitus and diabetic nephropathy who was admitted to our hospital with acute uremic myopericarditis. Echocardiography demonstrated a fibrinous pericardial effusion. The patient was initiated on hemodialysis for hyperkalemia, metabolic acidosis, and uremia. He subsequently developed shock from cardiac tamponade, which required emergent pericardiocentesis. He was notably without tachycardia while he was hypotensive, and his admission electrocardiogram did not show typical ST- or PR-segment changes typically associated with acute pericarditis. This case highlights important differences between uremic pericarditis and other prevalent types of acute pericarditis, including the lack of tachycardia during tamponade and normal electrocardiography. Uremic pericarditis is now a less common diagnosis. It is often seen in the setting of previously undiagnosed advanced kidney disease or when patients are ineffectively dialyzed. Given its atypical features, low incidence, and adverse attendant complications, internists must maintain a high degree of suspicion to correctly diagnose acute uremic pericarditis.
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Affiliation(s)
- Daniel Restrepo
- From the Hospital Medicine Unit and the Core Educator Faculty and Renal Unit, Department of Medicine, Massachusetts General Hospital and Harvard Medical School, the Heart and Vascular Center, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts
| | - Muthiah Vaduganathan
- From the Hospital Medicine Unit and the Core Educator Faculty and Renal Unit, Department of Medicine, Massachusetts General Hospital and Harvard Medical School, the Heart and Vascular Center, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts
| | - Andrew Z Fenves
- From the Hospital Medicine Unit and the Core Educator Faculty and Renal Unit, Department of Medicine, Massachusetts General Hospital and Harvard Medical School, the Heart and Vascular Center, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts
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Restrepo D, Hunt D, Miloslavsky E. Transforming traditional shadowing: engaging millennial learners through the active apprenticeship. Clin Teach 2018; 17:31-35. [PMID: 30467984 DOI: 10.1111/tct.12975] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Daniel Restrepo
- Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Daniel Hunt
- Emory University School of Medicine, Atlanta, Georgia, USA
| | - Eli Miloslavsky
- Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts, USA
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Restrepo D, Kochav J, Goodheart AE, Jain CC, Stern TA. The Importance of Identifying Myoclonus in the Setting of Mental Status Abnormalities: Differential Diagnosis and Treatment. Prim Care Companion CNS Disord 2016; 18. [DOI: 10.4088/pcc.16f01990] [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: 10/21/2022] Open
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21
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Aristizabal Sierra D, Herrero-Garcia J, Restrepo D, Vicente A. Diboson anomaly: Heavy Higgs resonance and QCD vectorlike exotics. Int J Clin Exp Med 2016. [DOI: 10.1103/physrevd.93.015012] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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22
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Buitrago S, Franken T, Leyssen G, Osorio S, Smets S, Restrepo D, Triana H, Chaparro A. A Web-based Tool for Operational Decision Making and IWRM. ACTA ACUST UNITED AC 2016. [DOI: 10.1016/j.proeng.2016.07.417] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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23
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Restrepo D, Laconi NS, Alcantar NA, West LA, Buttice AL, Patel S, Kayton ML. Inhibition of heparin precipitation, bacterial growth, and fungal growth with a combined isopropanol-ethanol locking solution for vascular access devices. J Pediatr Surg 2015; 50:472-7. [PMID: 25746710 DOI: 10.1016/j.jpedsurg.2014.07.003] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/10/2013] [Revised: 07/11/2014] [Accepted: 07/11/2014] [Indexed: 11/17/2022]
Abstract
BACKGROUND Clinical reports of ethanol-lock use for the prevention of catheter-related bloodstream infections have been marked by the occurrence of serious catheter occlusions, particularly among children with mediports. We hypothesized that precipitate forms when ethanol mixes with heparin at the concentrations relevant for vascular access devices, but that the use of a combination of two alcohols, ethanol and isopropanol, would diminish heparin-related precipitation, while retaining anti-bacterial and anti-fungal effects. METHODS Heparin (0-100units/mL) was incubated in ethanol-water solutions (30%-70% vol/vol) or in an aqueous solution containing equal parts (35% and 35% vol/vol) of isopropanol and ethanol. Precipitation at temperatures from 4 to 40°C was measured in nephelometric turbidity units using a benchtop turbidimeter. Growth of Escherichia coli, Staphylococcus aureus, and Candida albicans colonies were measured following exposure to solutions of ethanol or isopropanol-ethanol. Groupwise comparisons were performed using analysis of variance with Bonferroni-corrected, post-hoc T-testing. RESULTS Seventy percent ethanol and heparin exhibit dose-dependent precipitation that is pronounced and significant at the concentrations typically used in mediports (p<0.05). Precipitate is significantly reduced by use of a combined 35% isopropanol-35% ethanol solution rather than 70% ethanol (p<0.05), while maintaining the solution's anti-bacterial and anti-fungal properties. On the other hand, although ethanol solutions under 70% form less precipitate with heparin, such concentrations are also less effective at bacterial colony inhibition than solutions of either 70% ethanol or 35% isopropanol-35% ethanol (p<0.05). CONCLUSIONS A combined 35% isopropanol-35% ethanol locking solution inhibits bacterial and fungal growth similarly to 70% ethanol, but results in less precipitate than 70% ethanol when exposed to heparin. Further study of a combined isopropanol-ethanol locking solution for the prevention of catheter-related bloodstream infections should focus on the determination as to whether such a locking solution may reduce the rate of precipitation-related catheter occlusion, and whether it may be administered with low systemic toxicity.
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Affiliation(s)
- Daniel Restrepo
- Department of Surgery, Division of Pediatric Surgery, The University of South Florida Morsani College of Medicine, Tampa, FL, USA
| | - Nicholas S Laconi
- Department of Surgery, Division of Pediatric Surgery, The University of South Florida Morsani College of Medicine, Tampa, FL, USA
| | - Norma A Alcantar
- Department of Chemical & Biomedical Engineering, The University of South Florida, Tampa, FL, USA
| | - Leigh A West
- Florida Center of Excellence for Drug Discovery and Innovation (CDDI), The University of South Florida, Tampa, FL, USA
| | - Audrey L Buttice
- Department of Chemical & Biomedical Engineering, The University of South Florida, Tampa, FL, USA
| | - Saumil Patel
- Department of Pharmacy, Tampa General Hospital, Tampa, FL, USA
| | - Mark L Kayton
- Department of Surgery, Division of Pediatric Surgery, The University of South Florida Morsani College of Medicine, Tampa, FL, USA; Department of Surgery, Goryeb Children's Hospital, Morristown, NJ, USA.
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Rolen SH, Salcedo E, Restrepo D, Finger TE. Differential localization of NT-3 and TrpM5 in glomeruli of the olfactory bulb of mice. J Comp Neurol 2014; 522:1929-40. [PMID: 24288162 DOI: 10.1002/cne.23512] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2013] [Revised: 10/25/2013] [Accepted: 11/26/2013] [Indexed: 12/13/2022]
Abstract
Olfactory sensory neurons that express transient receptor potential channel M5 (TrpM5) or neurotrophin-3 (NT-3) project to defined clusters of glomeruli situated ventrally in the main olfactory bulb. Using genetically labeled mice, we investigated whether expression of NT-3-driven βgal and TrpM5-driven GFP marked overlapping sets of glomeruli and whether expression of these markers was coordinated. Our results indicate that these markers largely characterize independent sets of olfactory sensory neuron axons and glomeruli. Further, in glomeruli in which both TrpM5-GFP and NT-3-βgal labeled axons occur, they are expressed independently. The nature of staining for these two markers also differs within glomeruli. Within each labeled TrpM5-positive glomerulus, the level of TrpM5-GFP expression was similar throughout the glomerular neuropil. In contrast, NT-3-driven βgal expression levels are heterogeneous even within heavily labeled glomeruli. In addition, a population of very small TrpM5-GFP positive glomeruli is apparent while no similar populations of NT-3-βgal glomeruli are evident. Taken together, these data suggest that TrpM5 and NT-3 characterize two largely independent receptor populations both conveying odorant information to the ventral olfactory bulb.
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Affiliation(s)
- S H Rolen
- Department of Cell and Developmental Biology, University of Colorado Anschutz Medical Campus, Aurora, Colorado, 80045
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Keeney JG, O'Bleness MS, Anderson N, Davis JM, Arevalo N, Busquet N, Chick W, Rozman J, Hölter SM, Garrett L, Horsch M, Beckers J, Wurst W, Klingenspor M, Restrepo D, de Angelis MH, Sikela JM. Generation of mice lacking DUF1220 protein domains: effects on fecundity and hyperactivity. Mamm Genome 2014; 26:33-42. [PMID: 25308000 DOI: 10.1007/s00335-014-9545-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2014] [Accepted: 09/01/2014] [Indexed: 12/30/2022]
Abstract
Sequences encoding DUF1220 protein domains show the most extreme human lineage-specific copy number increase of any coding region in the genome and have been linked to human brain evolution. In addition, DUF1220 copy number (dosage) has been implicated in influencing brain size within the human species, both in normal populations and in individuals associated with brain size pathologies (1q21-associated microcephaly and macrocephaly). More recently, increasing dosage of a subtype of DUF1220 has been linked with increasing severity of the primary symptoms of autism. Despite these intriguing associations, a function for these domains has not been described. As a first step in addressing this question, we have developed the first transgenic model of DUF1220 function by removing the single DUF1220 domain (the ancestral form) encoded in the mouse genome. In a hypothesis generating exercise, these mice were evaluated by 197 different phenotype measurements. While resulting DUF1220-minus (KO) mice show no obvious anatomical peculiarities, they exhibit a significantly reduced fecundity (χ(2) = 19.1, df = 2, p = 7.0 × 10(-5)). Further extensive phenotypic analyses suggest hyperactivity (p < 0.05) of DUF1220 mice and changes in gene expression levels of brain associated with distinct neurological functions and disease. Other changes that met statistical significance include an increase in plasma glucose concentration (as measured by area under the curve, AUC 0-30 and AUC 30-120) in male mutants, fasting glucose levels, reduce sodium levels in male mutants, increased levels of the liver functional indicator ALAT/GPT in males, levels of alkaline phosphatase (also an indicator of liver function), mean R and SR amplitude by electrocardiography, elevated IgG3 levels, a reduced ratio of CD4:CD8 cells, and a reduced frequency of T cells; though it should be noted that many of these differences are quite small and require further examination. The linking of DUF1220 loss to a hyperactive phenotype is consistent with separate findings in which DUF1220 over expression results in a down-regulation of mitochondrial function, and potentially suggests a role in developmental metabolism. Finally, the substantially reduced fecundity we observe associated with KO mice argues that the ancestral DUF1220 domain provides an important biological functionthat is critical to survivability and reproductive success.
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Affiliation(s)
- J G Keeney
- Department of Biochemistry and Molecular Genetics and Human Medical Genetics and Neuroscience Programs, University of Colorado School of Medicine, Anschutz Medical Campus, Aurora, CO, 80045, USA
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de Campos F, Éboli OJP, Hirsch M, Magro MB, Porod W, Restrepo D, Valle JWF. Probing neutrino oscillations in supersymmetric models at the Large Hadron Collider. Int J Clin Exp Med 2010. [DOI: 10.1103/physrevd.82.075002] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Nath P, Nelson B, Davoudiasl H, Dutta B, Feldman D, Liu Z, Han T, Langacker P, Mohapatra R, Valle J, Pilaftsis A, Zerwas D, AbdusSalam S, Adam-Bourdarios C, Aguilar-Saavedra J, Allanach B, Altunkaynak B, Anchordoqui LA, Baer H, Bajc B, Buchmueller O, Carena M, Cavanaugh R, Chang S, Choi K, Csáki C, Dawson S, de Campos F, De Roeck A, Dührssen M, Éboli O, Ellis J, Flächer H, Goldberg H, Grimus W, Haisch U, Heinemeyer S, Hirsch M, Holmes M, Ibrahim T, Isidori G, Kane G, Kong K, Lafaye R, Landsberg G, Lavoura L, Lee JS, Lee SJ, Lisanti M, Lüst D, Magro M, Mahbubani R, Malinsky M, Maltoni F, Morisi S, Mühlleitner M, Mukhopadhyaya B, Neubert M, Olive K, Perez G, Pérez PF, Plehn T, Pontón E, Porod W, Quevedo F, Rauch M, Restrepo D, Rizzo T, Romão J, Ronga F, Santiago J, Schechter J, Senjanović G, Shao J, Spira M, Stieberger S, Sullivan Z, Tait TM, Tata X, Taylor T, Toharia M, Wacker J, Wagner C, Wang LT, Weiglein G, Zeppenfeld D, Zurek K. The Hunt for New Physics at the Large Hadron Collider. ACTA ACUST UNITED AC 2010. [DOI: 10.1016/j.nuclphysbps.2010.03.001] [Citation(s) in RCA: 100] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Jones S, Restrepo D, Kasowitz A, Korenstein D, Wallenstein S, Schneider A, Keller MJ. Risk factors for decreased bone density and effects of HIV on bone in the elderly. Osteoporos Int 2008; 19:913-8. [PMID: 18071649 DOI: 10.1007/s00198-007-0524-8] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/17/2007] [Accepted: 10/19/2007] [Indexed: 10/22/2022]
Abstract
UNLABELLED Most studies of bone density in HIV-infected individuals focus on young men. This study compares differences in bone density in elderly HIV positive men and women to HIV negative controls. Bone density was lower in the lumbar spine and hip in the HIV-infected group. Antiretrovirals may be associated with decreased bone mineralization. INTRODUCTION Individuals with human immunodeficiency virus (HIV) may be at increased risk for osteoporosis. Prolonged exposures to HIV and/or antiretroviral therapy are possible causes for this association. This study compares differences in bone mineral density (BMD) in elderly HIV positive men and women to HIV negative controls. METHODS A cross-sectional study was conducted among 57 HIV-infected and 47 HIV negative subjects over age 55. BMD at the lumbar spine and total hip and markers of bone turnover were compared. RESULTS BMD was borderline lower in the lumbar spine and significantly lower in the hip in the HIV-infected group. Controlling for age, sex, race and body mass index, differences between the groups were significant at both sites. There was no difference in markers of bone turnover between the groups. Tenofovir use was significantly associated with decreased BMD at the spine while protease inhibitor use was significantly associated with decreased BMD at the hip. CONCLUSION Elderly men and women with HIV have lower bone mass than HIV negative controls. Decreased body mass index was the most important risk factor associated with decreased BMD. Bone demineralization was observed among HIV-infected subjects receiving either tenofovir or a protease inhibitor.
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Affiliation(s)
- S Jones
- Department of Medicine, Weill Medical College of Cornell University, New York, NY, USA
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Abstract
We report a case of a 28-year-old recipient of a cadaveric renal transplant who developed Aspergillus infection in the allograft without having disseminated disease. We review the previously reported cases of isolated Aspergillus in kidney transplant recipients and discuss the possible route of transmission in our patient. We also discuss the alternate but successful treatment that our patient received.
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Affiliation(s)
- E Linden
- Department of Medicine, Division of Nephrology, Mount Sinai Hospital, 1 Gustave L. Levy Place, New York, NY 10029, USA.
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Abstract
It has been shown that olfactory epithelium can be safely biopsied from the living, intact human being. Observations of the ultrastructure of this epithelium shows changes that can then be correlated with the etiology and degree of olfactory loss, allowing a greater understanding of both normal transduction and of the pathology of dysfunction. Examples of the common forms of olfactory dysfunction are presented and discussed. Additionally, the technique will allow additional immuno-histochemical and molecular study of the tissue, will increase the understanding of both normal and pathological function and should translate to new therapeutic regimens.
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Affiliation(s)
- Bruce W Jafek
- Rocky Mountain Taste and Smell Center, Department of Otolaryngology-Head and Neck Surgery, UCHSC (B-205), 4200 East Ninth Avenue, Denver, CO 80262, USA.
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Schaefer ML, Finger TE, Restrepo D. Variability of position of the P2 glomerulus within a map of the mouse olfactory bulb. J Comp Neurol 2001; 436:351-62. [PMID: 11438935] [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: 02/20/2023]
Abstract
Olfactory receptor neurons (ORNs) that express a common odorant receptor molecule target specific glomeruli in the olfactory bulb. We systematically assessed the location of the olfactory glomeruli that receive input from ORNs expressing P2 receptors in the P2-internal ribosome entry site-tau-lacZ mouse. We present a new mapping method that includes an Internet-accessible computer program for generating two- and three-dimensional maps of the glomerular sheet in the olfactory bulbs of mice. Cylindrical coordinates were used to define glomerular location: The coordinates were given as the anteroposterior (AP) distance parallel to the long axis of the bulb (rostrocaudal; RC) and angular measurements with origin defined by the remnant ependymal layer in the center of the granule cell layer in the bulb. Using this method, we can apply rigorous statistical methods to give objective estimates of position and variability. At the 95% confidence interval, the lateral P2 glomerulus lies at coordinates 1,008 microm +/- 306 microm AP x 146 degrees +/- 12 degrees, and the medial P2 glomerulus lies at 1,828 microm +/- 196 microm AP x 204 degrees +/- 8 degrees. We estimate that these coordinates encompass a domain containing 29 and 37 of the 1,800 glomeruli ( approximately 2%) for the lateral and medial glomeruli, respectively. Furthermore, the data reported here demonstrate that the rostrocaudal position of small P2 glomeruli is three times more variable than that of large glomeruli.
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Affiliation(s)
- M L Schaefer
- Department of Cellular and Structural Biology and Rocky Mountain Taste and Smell Center, University of Colorado Health Sciences Center, Denver, Colorado 80262, USA
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Schaefer ML, Young DA, Restrepo D. Olfactory fingerprints for major histocompatibility complex-determined body odors. J Neurosci 2001; 21:2481-7. [PMID: 11264322 PMCID: PMC6762408] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/19/2023] Open
Abstract
Recognition of individual body odors is analogous to human face recognition in that it provides information about identity. Individual body odors determined by differences at the major histocompatibility complex (MHC or H-2) have been shown to influence mate choice, pregnancy block, and maternal behavior in mice. Unfortunately, the mechanism and extent of the main olfactory bulb (MOB) and accessory olfactory bulb (AOB) involvement in the discrimination of animals according to H-2-type has remained ambiguous. Here we study the neuronal activation patterns evoked in the MOB in different individuals on exposure to these complex, biologically meaningful sensory stimuli. We demonstrate that body odors from H-2 disparate mice evoke overlapping but distinct maps of neuronal activation in the MOB. The spatial patterns of odor-evoked activity are sufficient to be used like fingerprints to predict H-2 identity using a novel computer algorithm. These results provide functional evidence for discrimination of H-2-determined body odors in the MOB, but do not preclude a role for the AOB. These data further our understanding of the neural strategies used to decode socially relevant odors.
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Affiliation(s)
- M L Schaefer
- Neuroscience Program, Rocky Mountain Taste and Smell Center, Department of Cellular and Structural Biology, University of Colorado Health Sciences Center, Denver, Colorado 80262, USA
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Abstract
An important step in establishing and utilizing a cell culture system for the in vitro study of olfaction is assessing whether the cultured cells possess physiological properties similar to those of mature olfactory neurons. Various investigators have successfully established proliferating cell lines from olfactory tissue, but few have demonstrated the characteristics of odor sensitivity of these cells. We successfully established cultured cell lines from adult human olfactory tissue obtained using an olfactory biopsy procedure and measured their ability to respond to odor stimulation using calcium imaging techniques. A subset of the human olfactory cells in culture displayed a distinct morphology and specifically expressed immunocytochemical markers characteristic of mature human olfactory neurons such as OMP, G(olf), NCAM and NST. Under defined growth conditions, these cultured cells responded to odorant mixes that have been previously shown to elicit intracellular calcium changes in acutely-isolated human olfactory neurons. These odorant-elicited calcium responses displayed characteristics similar to those found in mature human olfactory neurons. First, cultured cells responded with either increases or decreases in intracellular calcium. Second, increases in calcium were abolished by removal of extracellular calcium. Third, inhibitors of the olfactory signal transduction cascades reversibly blocked these odorant-elicited intracellular calcium changes. Our results demonstrate that cultures of adult human olfactory cells established from olfactory biopsies retain some of the in vivo odorant response characteristics of acutely isolated cells from the adult olfactory epithelium. This work has important ramifications for investigation of olfactory function and dysfunction using biopsy procedures and in vitro assays of odor sensitivity.
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Affiliation(s)
- G Gomez
- Monell Chemical Senses Center, Philadelphia, Pennsylvania 19104-3308, USA.
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Abstract
The expression of the gap junction subunit connexin 43 was studied in the olfactory epithelium of adult mice. In agreement with conclusions from previous immunohistochemical studies, we observed expression of mRNA encoding for connexin 43 in layers of the epithelium containing nuclei belonging to sustentacular cells. However, we also observed expression of connexin 43 mRNA in the layers containing nuclei belonging to mature olfactory receptor neurons (ORNs), immature ORNs, and basal cells. Connexin 43 mRNA expression was low in dorsomedial regions of the nasal cavity but higher ventrally. This differential regional distribution was consistent with expression in a transgenic mouse of a LacZ reporter gene driven by the proximal 6.5 kb of the connexin 43 promoter. LacZ was expressed in cells colabeled with antibody against olfactory marker protein (OMP), corroborating that mature ORNs express connexin 43. LacZ staining also was observed in sustentacular and basal cells and in immature ORNs. Double-label studies with antibodies against connexin 43 and OMP and expression of connexin 43 in the epithelium of bulbectomized mice were also consistent with expression of connexin 43 in mature ORNs. This is the first report of expression of a connexin subunit in mature ORNs. Our findings of connexin subunits in mature ORNs raise the novel possibility that gap junctions may play a fundamental role in information processing in the olfactory epithelium.
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Affiliation(s)
- C Zhang
- Department of Cellular and Structural Biology and the Rocky Mountain Taste and Smell Center, University of Colorado Health Sciences Center, Denver, Colorado 80262, USA.
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Gomez G, Rawson NE, Cowart B, Lowry LD, Pribitkin EA, Restrepo D. Modulation of odor-induced increases in [Ca(2+)](i) by inhibitors of protein kinases A and C in rat and human olfactory receptor neurons. Neuroscience 2000; 98:181-9. [PMID: 10858624 DOI: 10.1016/s0306-4522(00)00112-3] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Protein kinases A and C have been postulated to exert multiple effects on different elements of signal transduction pathways in olfactory receptor neurons. However, little is known about the modulation of olfactory responses by protein kinases in intact olfactory receptor neurons. To further elucidate the details of the modulation of odorant responsiveness by these protein kinases, we investigated the action of two protein kinase inhibitors: H89, an inhibitor of protein kinase A, and N-myristoylated EGF receptor, an inhibitor of protein kinase C, on odorant responsiveness in intact olfactory neurons. We isolated individual olfactory neurons from the adult human and rat olfactory epithelium and measured responses of the isolated cells to odorants or biochemical activators that have been shown to initiate cyclic AMP or inositol 1,4,5-trisphospate production in biochemical preparations. We employed calcium imaging techniques to measure odor-elicited changes in intracellular calcium that occur over several seconds. In human olfactory receptor neurons, the protein kinase A and C inhibitors affected the responses to different sets of odorants. In rats, however, the protein kinase C inhibitor affected responses to all odorants, while the protein kinase A inhibitor had no effect. In both species, the effect of inhibition of protein kinases was to enhance the elevation and block termination of intracellular calcium levels elicited by odorants. Our results show that protein kinases A and C may modulate odorant responses of olfactory neurons by regulating calcium fluxes that occur several seconds after odorant stimulation. The effects of protein kinase C inhibition are different in rat and human olfactory neurons, indicating that species differences are an important consideration when applying data from animal studies to apply to humans.
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Affiliation(s)
- G Gomez
- Monell Chemical Senses Center, 3500 Market Street, Philadelphia, PA 19104, USA.
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Restrepo D. Proceedings of the symposium on adaptation in vision and olfaction held at the XXI meeting of AChemS on april 15, 1999. Chem Senses 2000; 25:471. [PMID: 10944512 DOI: 10.1093/chemse/25.4.471] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- D Restrepo
- Rocky Mountain Taste and Smell Center and Department of Cellular and Structural Biology, University of Colorado Health Sciences Center, Denver, CO 80262, USA
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Rawson NE, Eberwine J, Dotson R, Jackson J, Ulrich P, Restrepo D. Expression of mRNAs encoding for two different olfactory receptors in a subset of olfactory receptor neurons. J Neurochem 2000; 75:185-95. [PMID: 10854261 DOI: 10.1046/j.1471-4159.2000.0750185.x] [Citation(s) in RCA: 67] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Evidence has accumulated to support a model for odorant detection in which individual olfactory receptor neurons (ORNs) express one of a large family of G protein-coupled receptor proteins that are activated by a small number of closely related volatile chemicals. However, the issue of whether an individual ORN expresses one or multiple types of receptor proteins has yet to be definitively addressed. Physiological data indicate that some individual ORNs can be activated by odorants differing substantially in structure and/or perceived quality, suggesting multiple receptors or one nonspecific receptor per cell. In contrast, molecular biological studies favor a scheme with a single, fairly selective receptor per cell. The present studies directly assessed whether individual rat ORNs can express multiple receptors using single-cell PCR techniques with degenerate primers designed to amplify a wide variety of receptor sequences. We found that whereas only a single OR sequence was obtained from most ORNs examined, one ORN produced two distinct receptor sequences that represented different receptor gene families. Double-label in situ hybridization studies indicated that a subset of ORNs co-express two distinct receptor mRNAs. A laminar segregation analysis of the cell nuclei of ORNs labeled with the two OR mRNA probes showed that for one probe, the histogram of the distribution of the cell nuclei along the depth of the epithelium was bimodal, with one peak overlapping the (unimodal) histogram for the other probe. These results are consistent with co-expression of two OR mRNAs in a population of single ORNs.
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Affiliation(s)
- N E Rawson
- Monell Chemical Senses Center, and. Department of Pharmacology, University of Pennsylvania, Philadelphia, Pennsylvania, USA.
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Nibu K, Li G, Zhang X, Rawson NE, Restrepo D, Kaga K, Lowry LD, Keane WM, Rothstein JL. Olfactory neuron-specific expression of NeuroD in mouse and human nasal mucosa. Cell Tissue Res 1999; 298:405-14. [PMID: 10639731 DOI: 10.1007/s004419900098] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/29/2022]
Abstract
Human olfactory neuroepithelium (OE) is situated within the olfactory cleft of the nasal cavity and has the characteristic property of continually regenerating neurons during the lifetime of the individual. This regenerative ability of OE provides a unique model for neuronal differentiation, but little is known about the structure and biology of human olfactory mucosa. Thus, to better understand neurogenesis in human OE, we studied the expression of olfactory marker protein (OMP), TrkB and NeuroD in human nasal biopsies and autopsy specimens and compared these data with those obtained from normal and regenerating mouse OE. We show that NeuroD and TrkB are coordinately expressed in human OE. Thus, by using these markers we have been able to extend the known boundaries of the human OE to include the inferior middle turbinate. In normal mouse OE, TrkB and OMP expression overlap in cells closest to the superficial layer, but TrkB is expressed more strongly in the lower region of this layer. In contrast, NeuroD expression is more basally restricted in a region just above the globose basal cells. These characteristic expression patterns of OMP, TrkB and NeuroD were also observed in the regenerating mouse OE induced by axotomy. These results support a role of NeuroD and brain-derived neurotrophic actor (BDNF), the preferred ligand for TrkB, in the maintenance of the olfactory neuroepithelium in humans and mice.
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Affiliation(s)
- K Nibu
- Department of Otolaryngology-Head and Neck Surgery, Kimmel Cancer Institute, Thomas Jefferson University, Jefferson Medical College, Philadelphia, PA 19087, USA
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41
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Abstract
Stimulation of olfactory receptor neurons (ORNs) with odors elicits an increase in the concentration of cAMP leading to opening of cyclic nucleotide-gated (CNG) channels and subsequent depolarization. Although opening of CNG channels is thought to be the main mechanism mediating signal transduction, modulation of other ion conductances by odorants has been postulated. To determine whether K+ conductances are modulated by odorants in mammalian ORNs, we examined the response of rat ORNs to odors by recording membrane current under perforated-patch conditions. We find that rat ORNs display two predominant types of responses. Thirty percent of the cells responded to odorants with activation of a CNG conductance. In contrast, in 55% of the ORNs, stimulation with odorants inhibited a voltage-activated K+ conductance (IKo). In terms of pharmacology, ion permeation, outward rectification, and time course for inactivation, IKo resembled a delayed rectifier K+ conductance. The effect of odorants on IKo was specific (only certain odorants inhibited IKo in each ORN) and concentration dependent, and there was a significant latency between arrival of odorants to the cell and the onset of suppression. These results indicate that indirect suppression of a K+ conductance (IKo) by odorants plays a role in signal transduction in mammalian ORNs.
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Affiliation(s)
- F W Lischka
- Monell Chemical Senses Center, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
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Lischka FW, Zviman MM, Teeter JH, Restrepo D. Characterization of inositol-1,4,5-trisphosphate-gated channels in the plasma membrane of rat olfactory neurons. Biophys J 1999; 76:1410-22. [PMID: 10049323 PMCID: PMC1300119 DOI: 10.1016/s0006-3495(99)77302-9] [Citation(s) in RCA: 31] [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: 11/22/2022] Open
Abstract
It is generally accepted that inositol-1,4,5-trisphosphate (InsP3) plays a role in olfactory transduction. However, the precise mode of action of InsP3 remains controversial. We have characterized the conductances activated by the addition of 10 microM InsP3 to excised patches of soma plasma membrane from rat olfactory neurons. InsP3 induced current fluctuations in 25 of 121 inside-out patches. These conductances could be classified into two groups according to the polarity of the current at a holding potential of +40 to +60 mV (with Ringer's in the pipette and pseudointracellular solution in the bath). Conductances mediating outward currents could be further divided into large- (64 +/- 4 pS, n = 4) and small- (16 +/- 1.7 pS, n = 11) conductance channels. Both small- and large-conductance channels were nonspecific cation channels. The large-conductance channel displayed bursting behavior at +40 mV, with flickering increasing at negative holding potentials to the point where single-channel currents were no longer discernible. The small-conductance channel did not display flickering behavior. The conductance mediating inward currents at +40 to +60 mV reversed at +73 +/- 4 mV (n = 4). The current traces displayed considerable fluctuations, and single-channel currents could not be discerned. The current fluctuations returned to baseline after removal of InsP3. The power density spectrum for the excess noise generated by InsP3 followed a 1/f dependence consistent with conductance fluctuations in the channel mediating this current, although other mechanisms are not excluded. These experiments demonstrate the presence of plasma membrane InsP3-gated channels of different ionic specificity in olfactory receptor cells.
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Affiliation(s)
- F W Lischka
- Monell Chemical Senses Center, Philadelphia, Pennsylvania 19104, USA
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Rawson NE, Gomez G, Cowart B, Restrepo D. The use of olfactory receptor neurons (ORNs) from biopsies to study changes in aging and neurodegenerative diseases. Ann N Y Acad Sci 1998; 855:701-7. [PMID: 9929674 DOI: 10.1111/j.1749-6632.1998.tb10648.x] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.7] [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: 11/30/2022]
Abstract
A gradual loss of olfactory capability with age and in a number of neurodegenerative diseases is common, and mechanisms underlying these losses are not understood. We determined the feasibility of using ORNs obtained from olfactory epithelial biopsies to identify possible changes in ORN function that may contribute to olfactory impairment in these individuals. ORNs from nine healthy subjects (66-84 yr), three patients with Alzheimer's disease and one with multi-infarct dementia were studied with calcium imaging techniques and two odorant mixtures. Seventy-five viable ORNs were studied; 53% of these were odorant responsive, and twenty percent of these responded to both odorant mixtures. In contrast, 25% of 173 ORNs from younger subjects were odorant responsive, and none of these responded to both odorant mixtures. The proportion of cells responding to each of the odorant mixtures also differed between older and younger subjects. These studies demonstrate the feasibility of this approach to examine age or disease-associated changes in neuronal function. Further, age-related changes in ORN selectivity may contribute to changes in olfactory performance.
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Affiliation(s)
- N E Rawson
- Monell Chemical Senses Center, Philadelphia, Pennsylvania 19104-3308, USA.
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44
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Abstract
Considerable progress has been made in the understanding of transduction mechanisms in olfactory receptor neurons (ORNs) over the last decade. Odorants pass through a mucus interface before binding to odorant receptors (ORs). The molecular structure of many ORs is now known. They belong to the large class of G protein-coupled receptors with seven transmembrane domains. Binding of an odorant to an OR triggers the activation of second messenger cascades. One second messenger pathway in particular has been extensively studied; the receptor activates, via the G protein Golf, an adenylyl cyclase, resulting in an increase in adenosine 3',5'-cyclic monophosphate (cAMP), which elicits opening of cation channels directly gated by cAMP. Under physiological conditions, Ca2+ has the highest permeability through this channel, and the increase in intracellular Ca2+ concentration activates a Cl- current which, owing to an elevated reversal potential for Cl-, depolarizes the olfactory neuron. The receptor potential finally leads to the generation of action potentials conveying the chemosensory information to the olfactory bulb. Although much less studied, other transduction pathways appear to exist, some of which seem to involve the odorant-induced formation of inositol polyphosphates as well as Ca2+ and/or inositol polyphosphate -activated cation channels. In addition, there is evidence for odorant-modulated K+ and Cl- conductances. Finally, in some species, ORNs can be inhibited by certain odorants. This paper presents a comprehensive review of the biophysical and electrophysiological evidence regarding the transduction processes as well as subsequent signal processing and spike generation in ORNs.
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Affiliation(s)
- D Schild
- Physiologisches Institut, Universität Göttingen, Germany
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Rawson NE, Gomez G, Cowart B, Brand JG, Lowry LD, Pribitkin EA, Restrepo D. Selectivity and response characteristics of human olfactory neurons. J Neurophysiol 1997; 77:1606-13. [PMID: 9084623 DOI: 10.1152/jn.1997.77.3.1606] [Citation(s) in RCA: 60] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Transduction mechanisms were investigated in human olfactory neurons by determining characteristics of odorant-induced changes in intracellular calcium concentration ([Ca2+]i). Olfactory neurons were freshly isolated from nasal biopsies, allowed to attach to coverslips, and loaded with the calcium-sensitive indicator fura-2. Changes in [Ca2+]i were studied in response to exposure to individual odors, or odorant mixtures composed to distinguish between transduction pathways mediated by adenosine 3'5'-monophosphate (cAMP; mix A) or inositol 1,4,5-trisphosphate (InsP3; mix B). Overall, 52% of biopsies produced one or more odorant-responsive olfactory neurons, whereas 24% of all olfactory neurons tested responded to odorant exposure with a change in [Ca2+]i. As in olfactory neurons from other species, the data suggest that odorant exposure elicited calcium influx via second-messenger pathways involving cAMP or InsP3. Unlike olfactory neurons from other species that have been tested, some human olfactory neurons responded to odorants with decreases in [Ca2+]i. Also in contrast with olfactory neurons from other species, human olfactory neurons were better able to discriminate between odorant mixtures in that no neuron responded to more than one type of odor or mixture. These results suggest the presence of a previously unreported type of olfactory transduction mechanism, and raise the possibility that coding of odor qualities in humans may be accomplished to some degree differently than in other vertebrates, with the olfactory neuron itself making a greater contribution to the discrimination process.
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Affiliation(s)
- N E Rawson
- Monell Chemical Senses Center, Philadelphia, Pennsylvania, USA
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Dellacorte C, Restrepo D, Menco BP, Andreini I, Kalinoski DL. G alpha 9/G alpha 11: immunolocalization in the olfactory epithelium of the rat (Rattus rattus) and the channel catfish (Ictalurus punctatus). Neuroscience 1996; 74:261-73. [PMID: 8843091 DOI: 10.1016/0306-4522(96)00115-7] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The immunohistochemical localization of G alpha 9/G alpha 11 was studied in the olfactory and respiratory epithelium of two representative vertebrates, the rat and the channel catfish. Localization in the rat was found at the apical surface of cells in the epithelium and within nerve tracts in the lamina propria. Immunostaining of neuronal cilia and supporting cell microvilli was confirmed by electron microscopy. Immunoreactivity on the ipsilateral neuroepithelium was abolished five weeks following unilateral bulbectomy. An emergence of patchy immunoreactivity was found, however, after fifteen weeks. In catfish, G alpha 9/G alpha 11 antigenicity was found at the apical surface of cells within the olfactory epithelium, at supranuclear regions within some cell bodies and in basal nerve tracts of the olfactory rosette. Immunoreactivity was removed with unilateral bulbectomy. Specific labelling in both rat and catfish was eliminated by preincubation of the G alpha 9/G alpha 11 antibodies with the cognate peptide. Proteins were extracted from olfactory tissues of both species and solubilized. Using western blotting, bands corresponding in apparent molecular weight to a 38,000 mol. wt protein were found. These data demonstrate the presence of G alpha 9/G alpha 11 in the olfactory tissues of these vertebrates and suggest a role in olfaction for this class of G-protein.
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Affiliation(s)
- C Dellacorte
- Monell Chemical Senses Center, Philadelphia, PA 19104, USA
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Gomez G, Restrepo D, Rawson N, Lowry LD, Keane WM, Rothstein JL. Induction of differentiation of human olfactory neuroblastoma cells into odorant-responsive cells. Neuroscience 1996; 74:567-77. [PMID: 8865206 DOI: 10.1016/0306-4522(96)00143-1] [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] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Olfactory neuroblastoma is a rare malignancy of the olfactory mucosa that may be derived from the olfactory epithelium. To characterize this tumor, we cultured olfactory neuroblastoma cells in the presence or absence of growth factors (transforming growth factor alpha and basic fibroblast growth factor) known to affect olfactory tissue and assessed their responsiveness to known odorants by measuring changes in intracellular calcium. Untreated cells did not respond to odorants. Basic fibroblast growth factor treatment had cytotoxic effects, and treated cells did not respond to odorants. Transforming growth factor alpha treatment resulted in the induction of odor responsiveness in these cells. Cells responded to odorants at 100 nM to 100 microM concentrations and responded with both increases and decreases in intracellular calcium. Increases in intracellular calcium were mediated by a calcium influx and were reversibly blocked by compounds known to inhibit second messenger pathways in olfactory receptor neurons. The calcium responses of the olfactory neuroblastoma cells were thus specific to the odorants and similar to those found in olfactory receptor neurons. The results support the notion that olfactory neuroblastoma cells may be of olfactory origin and thus they can be used as a model cell line to study human olfaction.
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Affiliation(s)
- G Gomez
- Monell Chemical Senses Center, Philadelphia, PA 19104, USA
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Hayashi Y, Zviman MM, Brand JG, Teeter JH, Restrepo D. Measurement of membrane potential and [Ca2+]i in cell ensembles: application to the study of glutamate taste in mice. Biophys J 1996; 71:1057-70. [PMID: 8842242 PMCID: PMC1233560 DOI: 10.1016/s0006-3495(96)79306-2] [Citation(s) in RCA: 57] [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: 02/02/2023] Open
Abstract
We have studied the spectral properties of the voltage-sensitive dye, 1-(3-sulfonatopropyl)-4-[beta [2-(di-n-octylamino)-6-naphtyl]vinyl] pyridinium betaine (di-8-ANEPPS), and the Ca(2+)-sensitive dye, fura-2, in azolectin liposomes and in isolated taste buds from mouse. We find that the fluorescence excitation spectra of di-8-ANEPPS and fura-2 are largely nonoverlapping, allowing alternate ratio measurements of membrane potential and intracellular calcium ([Ca2+]i). There is a small spillover of di-8-ANEPPS fluorescence at the excitation wavelengths used for fura-2 (340 and 360 nm). However, voltage-induced changes in the fluorescence of di-8-ANEPPS, excited at the fura-2 wavelengths, are small. In addition, di-8-ANEPPS fluorescence is localized to the membrane, whereas fura-2 fluorescence is distributed throughout the cytoplasm. Because of this, the effect of spillover of di-8-ANEPPS fluorescence in the [Ca2+]i estimate is < 1%, under the appropriate conditions. We have applied this method to study of the responses of multiple taste cells within isolated taste buds. We show that membrane potential and [Ca2+]i can be measured alternately in isolated taste buds from mouse. Stimulation with glutamate and glutamate analogs indicates that taste cells express both metabotropic and ionotropic receptors. The data suggest that the receptors responding to 2-amino-4-phosphonobutyrate (L-AP4), presumably metabotropic L-glutamate receptors, do not mediate excitatory glutamate taste responses.
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Affiliation(s)
- Y Hayashi
- Monell Chemical Senses Center, University of Pennsylvania, Philadelphia, USA
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49
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Abstract
Olfactory receptor neurons respond to odorants with G-protein mediated increases in the concentration of cyclic adenosine 3',5'-monophosphate (cAMP) and/or inositol 1,4,5-trisphospahte (InsP3). These two second messengers directly regulate opening of cAMP- and InsP3-regulated conductances localized to the apical transduction compartments of the cell (cilia and olfactory knob). In the presence of physiological concentrations of extracellular Ca2+, these second messenger regulated conductances mediate influx of Ca2+ into the olfactory neuron resulting in large, localized increases in intracellular Ca2+ ([Ca2+]i). A significant advance in our understanding of the molecular mechanisms of olfaction is the recent realization that this increase in [Ca2+]i plays an important role as a "third messenger" in olfactory transduction. Second messenger dependent increases in [Ca2+]i cause opening of ciliary Ca(2+)-activated Cl-, cation and/ or K+ channels that can carry a large percentage of the generator current, thus amplifying the signal substantially. As a result of this sequence of events, the generator potential in olfactory neurons can be depolarizing, leading to excitation of the neuron, or hyperpolarizing, leading to suppression of basal action potential firing rate. This dual effect of odorants on olfactory neurons may play an important role in quality coding and in the ability to detect low concentrations of odorants, particularly in complex mixtures.
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Affiliation(s)
- D Restrepo
- Monell Chemical Senses Center, University of Pennsylvania, Philadelphia, 19104, USA.
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Zviman MM, Restrepo D, Teeter JH. Single taste stimuli elicit either increases or decreases in intracellular calcium in isolated catfish taste cells. J Membr Biol 1996; 149:81-8. [PMID: 8834115 DOI: 10.1007/s002329900009] [Citation(s) in RCA: 12] [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: 02/02/2023]
Abstract
Taste cells are specialized epithelial cells that respond to stimulation with release of neurotransmitters onto afferent nerves that innervate taste buds. In analogy to neurotransmitter release in other cells, it is expected that neurotransmitter release in taste cells is dependent on an increase in intracellular Ca2+ ([Ca2+]i). We have studied changes in [Ca2+]i elicited by the taste stimuli L- and D-arginine in isolated taste cells from the channel catfish (Ictalurus punctatus). In a sample of 119 cells, we found 15 cells responding to L-arginine, and 12 cells responding to D-arginine with an increase in [Ca2+]i. The response to L-arginine was inhibited by equimolar D-arginine in cells where D-arginine alone did not cause a change in [Ca2+]i, which is consistent with mediation of this response by a previously characterized L-arginine-gated nonspecific cation channel antagonized by D-arginine [31]. However, we also found that these taste stimuli elicited decreases in [Ca2+]i in substantial number of cells (6 for L-Arg, and 2 for D-Arg, n = 119). These observations suggest that stimulation of taste cells with sapid stimuli may result in simultaneous excitation and inhibition of different taste cells within the taste bud, which could be involved in local processing of the taste signal.
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Affiliation(s)
- M M Zviman
- Monell Chemical Senses Center, Philadelphia, PA 19104, USA
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