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Jain A, Perdomo D, Nagururu N, Li JA, Ward BK, Lauer AM, Creighton FX. SVPath: A Deep Learning Tool for Analysis of Stria Vascularis from Histology Slides. J Assoc Res Otolaryngol 2024:10.1007/s10162-024-00948-z. [PMID: 38760547 DOI: 10.1007/s10162-024-00948-z] [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] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2023] [Accepted: 04/18/2024] [Indexed: 05/19/2024] Open
Abstract
INTRODUCTION The stria vascularis (SV) may have a significant role in various otologic pathologies. Currently, researchers manually segment and analyze the stria vascularis to measure structural atrophy. Our group developed a tool, SVPath, that uses deep learning to extract and analyze the stria vascularis and its associated capillary bed from whole temporal bone histopathology slides (TBS). METHODS This study used an internal dataset of 203 digitized hematoxylin and eosin-stained sections from a normal macaque ear and a separate external validation set of 10 sections from another normal macaque ear. SVPath employed deep learning methods YOLOv8 and nnUnet to detect and segment the SV features from TBS, respectively. The results from this process were analyzed with the SV Analysis Tool (SVAT) to measure SV capillaries and features related to SV morphology, including width, area, and cell count. Once the model was developed, both YOLOv8 and nnUnet were validated on external and internal datasets. RESULTS YOLOv8 implementation achieved over 90% accuracy for cochlea and SV detection. nnUnet SV segmentation achieved a DICE score of 0.84-0.95; the capillary bed DICE score was 0.75-0.88. SVAT was applied to compare both the ears used in the study. There was no statistical difference in SV width, SV area, and average area of capillary between the two ears. There was a statistical difference between the two ears for the cell count per SV. CONCLUSION The proposed method accurately and efficiently analyzes the SV from temporal histopathology bone slides, creating a platform for researchers to understand the function of the SV further.
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Affiliation(s)
- Aseem Jain
- College of Medicine, University of Cincinnati, 231 Albert Sabin Way, Cincinnati, OH, 45267, USA.
| | - Dianela Perdomo
- Department of Otolaryngology-Head and Neck Surgery, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Nimesh Nagururu
- Department of Otolaryngology-Head and Neck Surgery, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Jintong Alice Li
- Department of Otolaryngology-Head and Neck Surgery, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Bryan K Ward
- Department of Otolaryngology-Head and Neck Surgery, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Amanda M Lauer
- Department of Otolaryngology-Head and Neck Surgery, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Francis X Creighton
- Department of Otolaryngology-Head and Neck Surgery, Johns Hopkins University School of Medicine, Baltimore, MD, USA
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Akbar AF, Perdomo D, Shou BL, Zhou AL, Ruck JM, Kilic A. Changes in Donor Utilization and Outcomes for Patients Bridged With Durable Left Ventricular Assist Device. ASAIO J 2024:00002480-990000000-00482. [PMID: 38728740 DOI: 10.1097/mat.0000000000002228] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/12/2024] Open
Abstract
We studied the impact of the 2018 heart allocation policy change on donor characteristics and posttransplant outcomes of left ventricular assist device (LVAD)-bridged heart transplant (HT) recipients. Left ventricular assist device-bridged adult HT recipients from October 2014 to October 2022 in the United Network for Organ Sharing database were categorized into old allocation policy (OAP) and new allocation policy (NAP) cohorts. Baseline characteristics, posttransplant outcomes, and subgroup analyses of unstable and stable LVAD-bridged recipients were assessed. The study included 7,384 HT recipients; 4,345 (58.8%) were transplanted in the OAP era and 3,039 (41.2%) in the NAP era. Old allocation policy recipients were most frequently status 1A at transplantation (71.1%), whereas NAP recipients were most frequently status 3 (40.0%), and status 4 (31.9%). Median donor sequence number (DSN) was higher in the NAP versus OAP era (9 vs. 3, p < 0.001). On multivariable analysis, NAP recipients had 20% higher 1 year mortality compared to OAP (adjusted hazard ratio [aHR] = 1.20 [95% confidence interval {CI}: 1.04-1.40], p = 0.01). Status 1 or 2 recipients had 28% higher 1 year mortality compared to status 1A (aHR = 1.28 [95% CI: 1.01-1.63], p = 0.04). Status 1 and 2 LVAD-supported recipients had higher mortality following the 2018 allocation change, indicating the need for closer surveillance of LVAD-bridged patients who may decompensate on the waitlist.
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Affiliation(s)
- Armaan F Akbar
- From the Division of Cardiac Surgery, Department of Surgery, Johns Hopkins School of Medicine, Baltimore, Maryland
| | - Dianela Perdomo
- Division of Thoracic Surgery, Department of Surgery, Johns Hopkins School of Medicine, Baltimore, Maryland
| | - Benjamin L Shou
- From the Division of Cardiac Surgery, Department of Surgery, Johns Hopkins School of Medicine, Baltimore, Maryland
| | - Alice L Zhou
- From the Division of Cardiac Surgery, Department of Surgery, Johns Hopkins School of Medicine, Baltimore, Maryland
| | - Jessica M Ruck
- Division of Thoracic Surgery, Department of Surgery, Johns Hopkins School of Medicine, Baltimore, Maryland
| | - Ahmet Kilic
- From the Division of Cardiac Surgery, Department of Surgery, Johns Hopkins School of Medicine, Baltimore, Maryland
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Perdomo D, Pebworth R, Lawton JS, Kilic A, Reddy RM, David EA, Odell DD, Yang SC. The Society of Thoracic Surgeons Looking to the Future Scholarship Program: A 15-Year Review. Ann Thorac Surg 2024; 117:866-872. [PMID: 37739113 DOI: 10.1016/j.athoracsur.2023.09.016] [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: 01/30/2023] [Revised: 08/29/2023] [Accepted: 09/05/2023] [Indexed: 09/24/2023]
Abstract
BACKGROUND It has been postulated that a possible barrier to pursuing cardiothoracic surgery is a lack of exposure and mentorship during training. In 2006, The Society of Thoracic Surgeons began the Looking to the Future Scholarship to expand interest in the field. Undecided trainees with limited exposure were prioritized in the selection process. This report summarizes the career outcomes of general surgery resident and medical student recipients. METHODS Scholarship recipients and nonrecipients (control) were queried in a Google search. The percentage of those who were cardiothoracic surgeons or in cardiothoracic training (%CTS) was calculated, as well as the percentage of female surgeons in cardiothoracic surgery. RESULTS From 2006 to 2021, there were 669 awardees. The %CTS was 63.7% for resident recipients and 31.4% for students, respectively. There was no significant difference in %CTS between resident and student recipients compared to nonrecipients. Notably, the percentage of female cardiothoracic surgeons was significantly greater for both resident and student recipients. CONCLUSIONS The majority of resident recipients are now in cardiothoracic surgery, comparable to nonrecipients. While there was no significant difference between the percentage of recipients and non-recipients in cardiothoracic surgery, these groups differed substantially as nonrecipients had greater exposure and commitment to the field at the time of application.
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Affiliation(s)
- Dianela Perdomo
- Division of Thoracic Surgery, Department of Surgery, Johns Hopkins School of Medicine, Baltimore, Maryland.
| | | | - Jennifer S Lawton
- Division of Cardiac Surgery, Department of Surgery, Johns Hopkins School of Medicine, Baltimore, Maryland
| | - Ahmet Kilic
- Division of Cardiac Surgery, Department of Surgery, Johns Hopkins School of Medicine, Baltimore, Maryland
| | - Rishindra M Reddy
- Department of Thoracic Surgery, University of Michigan, Ann Arbor, Michigan
| | - Elizabeth A David
- Division of Cardiothoracic Surgery, Department of Surgery, University of Colorado Anschutz Medical Campus, Aurora, Colorado
| | - David D Odell
- Department of Surgery, Canning Thoracic Institute, Northwestern University, Feinberg School of Medicine, Chicago, Illinois
| | - Stephen C Yang
- Division of Thoracic Surgery, Department of Surgery, Johns Hopkins School of Medicine, Baltimore, Maryland
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Jung D, Perdomo D, Ward BK. Historical Therapies for Suspected Autonomic Dysregulation in Meniere's Disease. Laryngoscope 2024; 134:535-542. [PMID: 37584400 DOI: 10.1002/lary.30944] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2023] [Revised: 07/14/2023] [Accepted: 07/24/2023] [Indexed: 08/17/2023]
Abstract
OBJECTIVE This narrative review examines how speculative belief that the autonomic nervous system causes Meniere's Disease (MD) led otolaryngologists to adopt invasive surgical procedures and medical treatments still offered today. DATA SOURCES Google Scholar, PubMed. REVIEW METHODS A comprehensive literature review (1860-2022) was performed using the terms "Meniere AND (sympathetic OR sympathectomy OR vasomotor OR cervical ganglion)," returning 5360 items. All abstracts were briefly reviewed, relevant publications selected for further study, and key articles discussed by all authors. As it became clear that betahistine was related to the historical narrative, an additional search was performed using "Betahistine AND Meniere AND (vasomotor OR sympathetic OR sympathectomy OR cervical ganglion OR autonomic)," which yielded 336 results. RESULTS In the 19th and 20th centuries, growing knowledge of human anatomy led the scientific community to speculate that autonomic dysregulation caused many medical conditions. Excessive sympathetic mediated vasomotor changes were thought to cause hypertension, ischemia, and tissue damage. Clinicians applied the hypothesis to MD, assigning the sympathetic nervous system responsible for vertigo secondary to paroxysmal vasospasm and for hearing loss to poor cochlear nutrition. Despite limited animal experiments and isolated clinical observations, otolaryngologists performed sympathectomies, and, in the 1970s, replaced the procedure with betahistine as an alternative medical treatment. CONCLUSION Premature excitement about a plausible hypothesis led to unnecessary and unwarranted operations. Despite absent evidence of sympathetic overactivation in MD, surgeons eagerly adopted sympathectomies, and later betahistine. Rigorous evaluation of the validity of these treatment practices is needed. LEVEL OF EVIDENCE 5 Laryngoscope, 134:535-542, 2024.
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Affiliation(s)
- Diane Jung
- Johns Hopkins School of Medicine, Baltimore, Maryland, U.S.A
| | - Dianela Perdomo
- Johns Hopkins School of Medicine, Baltimore, Maryland, U.S.A
| | - Bryan K Ward
- Department of Otolaryngology-Head & Neck Surgery, Johns Hopkins University, Baltimore, Maryland, U.S.A
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Alexandris AS, Lee Y, Lehar M, Alam Z, McKenney J, Perdomo D, Ryu J, Welsbie D, Zack DJ, Koliatsos VE. Traumatic Axonal Injury in the Optic Nerve: The Selective Role of SARM1 in the Evolution of Distal Axonopathy. J Neurotrauma 2023; 40:1743-1761. [PMID: 36680758 PMCID: PMC10460965 DOI: 10.1089/neu.2022.0416] [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] [Indexed: 01/22/2023] Open
Abstract
Traumatic axonal injury (TAI), thought to be caused by rotational acceleration of the head, is a prevalent neuropathology in traumatic brain injury (TBI). TAI in the optic nerve is a common finding in multiple blunt-force TBI models and hence a great model to study mechanisms and treatments for TAI, especially in view of the compartmentalized anatomy of the visual system. We have previously shown that the somata and the proximal, but not distal, axons of retinal ganglion cells (RGC) respond to DLK/LZK blockade after impact acceleration of the head (IA-TBI). Here, we explored the role of the sterile alpha and TIR-motif containing 1 (SARM1), the key driver of Wallerian degeneration (WD), in the progressive breakdown of distal and proximal segments of the optic nerve following IA-TBI with high-resolution morphological and classical neuropathological approaches. Wild type and Sarm1 knockout (KO) mice received IA-TBI or sham injury and were allowed to survive for 3, 7, 14, and 21 days. Ultrastructural and microscopic analyses revealed that TAI in the optic nerve is characterized by variable involvement of individual axons, ranging from apparent early disconnection of a subpopulation of axons to a range of ongoing axonal and myelin perturbations. Traumatic axonal injury resulted in the degeneration of a population of axons distal and proximal to the injury, along with retrograde death of a subpopulation of RGCs. Quantitative analyses on proximal and distal axons and RGC somata revealed that different neuronal domains exhibit differential vulnerability, with distal axon segments showing more severe degeneration compared with proximal segments and RGC somata. Importantly, we found that Sarm1 KO had a profound effect in the distal optic nerve by suppressing axonal degeneration by up to 50% in the first 2 weeks after IA-TBI, with a continued but lower effect at 3 weeks, while also suppressing microglial activation. Sarm1 KO had no evident effect on the initial traumatic disconnection and did not ameliorate the proximal optic axonopathy or the subsequent attrition of RGCs, indicating that the fate of different axonal segments in the course of TAI may depend on distinct molecular programs within axons.
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Affiliation(s)
| | - Youngrim Lee
- Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Mohamed Lehar
- Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
- Department of Otolaryngology—Head and Neck Surgery, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Zahra Alam
- Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - James McKenney
- Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Dianela Perdomo
- Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Jiwon Ryu
- Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Derek Welsbie
- Viterbi Family Department of Ophthalmology and Shiley Eye Institute, University of California San Diego, La Jolla, California, USA
| | - Donald J. Zack
- Department of Ophthalmology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
- Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
- Department of Neuroscience Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
- Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Vassilis E. Koliatsos
- Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
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Odeh R, Diehl ERM, Nixon SJ, Tisher CC, Klempner D, Sonke JK, Colquhoun TA, Li Q, Espinosa M, Perdomo D, Rosario K, Terzi H, Guy CL. A pilot randomized controlled trial of group-based indoor gardening and art activities demonstrates therapeutic benefits to healthy women. PLoS One 2022; 17:e0269248. [PMID: 35793277 PMCID: PMC9258874 DOI: 10.1371/journal.pone.0269248] [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] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2021] [Accepted: 05/10/2022] [Indexed: 11/18/2022] Open
Abstract
Background
There is mounting anecdotal and empirical evidence that gardening and art-making afford therapeutic benefits.
Objectives
This randomly controlled pilot study tested the hypothesis that participation in group-based indoor gardening or art-making activities for one hour twice a week for four weeks would provide quantifiably different therapeutic benefits to a population of healthy women ages 26–49.
Methods
A population of 42 volunteers was randomly assigned to parallel gardening or art-making treatment groups. A total of 36 participants initiated the treatment protocol and 32 (Gardening n = 15 and Art n = 17) received the interventions and completed all assessments. Treatments included eight one-hour group-based gardening or art intervention sessions. Self-report psychometric assessments were conducted for anxiety, depression symptomatology, mood disturbance, stress, satisfaction with discretionary social activities, and quality of life measures. Cardiac physiological data were also collected. Outcomes were measured at baseline, during, and post-intervention.
Results
Engaging in both gardening and art-making activities resulted in apparent therapeutic improvements for self-reported total mood disturbance, depression symptomatology, and perceived stress with different effect sizes following eight one-hour treatment sessions. Gardening also resulted in improvements for indications of trait anxiety. Based on time-course evidence, dosage responses were observed for total mood disturbance, perceived stress, and depression symptomatology for both gardening and art-making. However, gardening or art-making did not have an apparent influence on heart rate or blood pressure or result in marked improvement for satisfaction with discretionary leisure activities.
Conclusion
The data did not support the hypothesis of differential therapeutic benefits of gardening and art-making for healthy women. When taken together, group-based gardening or art-making can provide quantitatively measurable improvements in healthy women’s psychosocial health status that imply potentially important public health benefits.
Trial registration
ClinicalTrials.gov NCT03266120.
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Affiliation(s)
- Raymond Odeh
- Department of Environmental Horticulture, University of Florida, Gainesville, Florida, United States of America
| | - Elizabeth R. M. Diehl
- Wilmot Botanical Gardens, University of Florida, Gainesville, Florida, United States of America
| | - Sara Jo Nixon
- Department of Psychiatry, University of Florida, Gainesville, Florida, United States of America
| | - C. Craig Tisher
- Wilmot Botanical Gardens, University of Florida, Gainesville, Florida, United States of America
| | - Dylan Klempner
- Center for Arts in Medicine, University of Florida, Gainesville, Florida, United States of America
| | - Jill K. Sonke
- Center for Arts in Medicine, University of Florida, Gainesville, Florida, United States of America
| | - Thomas A. Colquhoun
- Department of Environmental Horticulture, University of Florida, Gainesville, Florida, United States of America
| | - Qian Li
- Health Outcomes & Biomedical Informatics, University of Florida, Gainesville, Florida, United States of America
| | - Maria Espinosa
- Department of Environmental Horticulture, University of Florida, Gainesville, Florida, United States of America
| | - Dianela Perdomo
- Department of Environmental Horticulture, University of Florida, Gainesville, Florida, United States of America
| | - Kaylee Rosario
- Department of Environmental Horticulture, University of Florida, Gainesville, Florida, United States of America
| | - Hannah Terzi
- Department of Environmental Horticulture, University of Florida, Gainesville, Florida, United States of America
| | - Charles L. Guy
- Department of Environmental Horticulture, University of Florida, Gainesville, Florida, United States of America
- * E-mail:
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Perdomo D. Should coronavirus policies remain in place to prevent future paediatric influenza deaths? J Med Ethics 2021; 48:medethics-2021-107982. [PMID: 34969776 PMCID: PMC8720637 DOI: 10.1136/medethics-2021-107982] [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] [Subscribe] [Scholar Register] [Received: 10/31/2021] [Accepted: 12/17/2021] [Indexed: 06/14/2023]
Abstract
The 2019-2020 to 2020-2021 influenza seasons in the USA saw a dramatic 99.5% decrease in paediatric mortality, with only one influenza death recorded during the latter season. This decrease has been attributed to a substantial reduction in transmission, resulting from the various restrictive measures enacted during the COVID-19 pandemic, onset March 2020. The relative disappearance of influenza raises specific policy questions, such as whether these measures should be kept in place after COVID-19 transmission reaches acceptable levels or herd immunity is achieved. Given the nature of these measures as liberty restricting, it is worth discussing their intended outcome and what values they promote. Do these measures in fact promote health, or simply give the comfort of safety while undermining long-term health and individual liberties? I argue that the year-long endurance of the pandemic well into 2021 may have flattened our value landscape into one where health reigns supreme. Discussions are underway regarding whether we should modify previously accepted health risks, such as the risk of contracting influenza. In this paper, I attempt to clarify the values that motivate our policies and discuss how our present historical context has appreciated the value of health. I also provide an analysis of various pandemic policies and their relation to influenza paediatric deaths. Ultimately, the cost of certain measures on values such as education, socialisation and liberty, among others, is too high to justify their use beyond regulating the spread of COVID-19.
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Affiliation(s)
- Dianela Perdomo
- Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
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Quesada Ocete B, Quesada Dorador A, Diez Albero L, Bochard-Villanueva B, Rubini-Costa R, Paya-Serrano R, Rubini-Puig R, Lopez-Valero L, Fernandez-Diaz C, Palanca-Gil V, Ruiz-Moliner C, Jimenez-Bello J, De La Espriella R, Perdomo D, Trejo-Velasco B. P1217Impact of diabetes mellitus in the clinical presentation and outcomes of atrial fibrillation. Europace 2018. [DOI: 10.1093/europace/euy015.699] [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] Open
Affiliation(s)
| | - A Quesada Dorador
- University General Hospital of Valencia, Department of Cardiology, Valencia, Spain
| | - L Diez Albero
- Faculty of Medicine, Catholic University of Valencia “San Vicente Martir”, Valencia, Spain
| | - B Bochard-Villanueva
- University General Hospital of Valencia, Department of Cardiology, Valencia, Spain
| | - R Rubini-Costa
- Faculty of Medicine, Catholic University of Valencia “San Vicente Martir”, Valencia, Spain
| | - R Paya-Serrano
- University General Hospital of Valencia, Department of Cardiology, Valencia, Spain
| | - R Rubini-Puig
- University General Hospital of Valencia, Emergency Department, Valencia, Spain
| | - L Lopez-Valero
- Faculty of Medicine, Catholic University of Valencia “San Vicente Martir”, Valencia, Spain
| | - C Fernandez-Diaz
- University General Hospital of Valencia, Department of Cardiology, Valencia, Spain
| | - V Palanca-Gil
- University General Hospital of Valencia, Department of Cardiology, Valencia, Spain
| | - C Ruiz-Moliner
- Faculty of Medicine, Catholic University of Valencia “San Vicente Martir”, Valencia, Spain
| | - J Jimenez-Bello
- University General Hospital of Valencia, Department of Cardiology, Valencia, Spain
| | - R De La Espriella
- University General Hospital of Valencia, Department of Cardiology, Valencia, Spain
| | - D Perdomo
- University General Hospital of Valencia, Department of Cardiology, Valencia, Spain
| | - B Trejo-Velasco
- University General Hospital of Valencia, Department of Cardiology, Valencia, Spain
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Lee C, Perdomo D, Czaja S, Schulz R. HISTORICAL TRENDS IN DEMENTIA FAMILY-CARE: A NEW GENERATION OF CAREGIVERS. Innov Aging 2017. [DOI: 10.1093/geroni/igx004.2911] [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: 11/13/2022] Open
Affiliation(s)
- C. Lee
- Psychiatry and Behavioral Sciences, University of Miami Miller School of Medicine, Miami, Florida,
| | - D. Perdomo
- Psychiatry and Behavioral Sciences, University of Miami Miller School of Medicine, Miami, Florida,
| | - S.J. Czaja
- Psychiatry and Behavioral Sciences, University of Miami Miller School of Medicine, Miami, Florida,
| | - R. Schulz
- University of Pittsburgh, Pittsburgh, Pennsylvania
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Tiffert T, Daw N, Perdomo D, Lew VL. A fast and simple screening test to search for specific inhibitors of the plasma membrane calcium pump. J Lab Clin Med 2001; 137:199-207. [PMID: 11241030 DOI: 10.1067/mlc.2001.113112] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
No specific inhibitors of the plasma membrane Ca(2+) pump have been found to date, limiting research on the particular contribution of this pump to the Ca(2+) homeostasis of animal cells. The search for Ca(2+) pump inhibitors may have been hampered by the lack of an efficient screening method to measure pump activity that would provide an alternative to the lengthy and costly adenosine triphosphatase or Ca(2+)-flux measurements. We propose here a novel screening method in which Ca(2+) pump inhibition is translated into easily measurable cell dehydration. Intact human red cells, suspended in Ca(2+)-containing, low-K(+) buffers were exposed to sequential additions of (1) ionophore A23187 (t = 0) to load the cells with Ca(2+); (2) CoCl(2) (t = 1 minute) to block ionophore-mediated Ca(2+) transport and to allow complete extrusion of the Ca(2+) load by the pump in less than 5 minutes; and (3) NaSCN (t = 6 minutes) to accelerate cell dehydration via Ca(2+)-sensitive K(+) channels when the Ca(2+) load is retained as a result of Ca(2+) pump inhibition. Samples were taken at 10 to 25 minutes after ionophore addition and delivered into hypotonic media containing about 45 mmol/L NaCl. Non-dehydrated cells-with normal, uninhibited pumps-instantly underwent lysis, whereas dehydrated cells-with inhibited pumps-resisted lysis, resulting in translucent or opaque samples, respectively, which were quantifiable by light-absorption measurements. Vanadate was used as a test substance to assess the effect of putative pump inhibitors. This method offers a cost-efficient and easily automated alternative for testing large numbers of natural or synthetic agents.
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Affiliation(s)
- T Tiffert
- Physiological Laboratory, University of Cambridge, United Kingdom
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Abstract
Previous studies have shown that ferriprotoporphyrin IX (FP) and non-heme iron have a marked inhibitory effect on the Ca(2+)-Mg(2+)-ATPase activity of isolated red cell membranes, the biochemical counterpart of the plasma membrane Ca(2+) pump (PMCA). High levels of membrane-bound FP and non-heme iron have been found in abnormal red cells such as sickle cells and malaria-infected red cells, associated with a reduced life span. It was important to establish whether sublytic concentrations of FP and non-heme iron would also inhibit the PMCA in normal red cells, to assess the possible role of these agents in the altered Ca(2+) homeostasis of abnormal cells. Active Ca(2+) extrusion by the plasma membrane Ca(2+) pump was measured in intact red cells that had been briefly preloaded with Ca(2+) by means of the ionophore A23187. The FP and nonheme iron concentrations used in this study were within the range of those applied to the isolated red cell membrane preparations. The results showed that FP caused a marginal inhibition ( approximately 20%) of pump-mediated Ca(2+) extrusion and that non-heme iron induced a slight stimulation of the Ca(2+) efflux (11-20%), in contrast to the marked inhibitory effects on the Ca(2+)-Mg(2+)-ATPase of isolated membranes. Thus, FP and non-heme iron are unlikely to play a significant role in the altered Ca(2+) homeostasis of abnormal red cells.
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Affiliation(s)
- T Tiffert
- Physiological Laboratory, University of Cambridge, Downing Street, Cambridge CB2 3EG, United Kingdom
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