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509 results on '"Koopman, A. S."'

1. Cost-effectiveness of CT perfusion for the detection of large vessel occlusion acute ischemic stroke followed by endovascular treatment: a model-based health economic evaluation study

Author

van Voorst, Henk, Hoving, Jan W., Koopman, Miou S., Daems, Jasper D., Peerlings, Daan, Buskens, Erik, Lingsma, Hester F., Beenen, Ludo F. M., de Jong, Hugo W. A. M., Berkhemer, Olvert A., van Zwam, Wim H., Roos, Yvo B. W. E. M., van Walderveen, Marianne A. A., van den Wijngaard, Ido, Dippel, Diederik W. J., Yoo, Albert J., Campbell, Bruce C. V., Kunz, Wolfgang G., Emmer, Bart J., and Majoie, Charles B. L. M.

Published
2024
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6. Association between computed tomography perfusion and the effect of intravenous alteplase prior to endovascular treatment in acute ischemic stroke

Author

Hoving, Jan W., van Voorst, Henk, Peerlings, Daan, Daems, Jasper D., Koopman, Miou S., Wouters, Anke, Kappelhof, Manon, LeCouffe, Natalie E., Treurniet, Kilian M., Bruggeman, Agnetha A. E., Rinkel, Leon A., van den Wijngaard, Ido R., Coutinho, Jonathan M., van der Lugt, Aad, Marquering, Henk A., Roos, Yvo B. W. E. M., Majoie, Charles B. L. M., and Emmer, Bart J.

Published
2023
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10. A runtime alterable epidemic model with genetic drift, waning immunity and vaccinations

Author

Getz, Wayne M, Salter, Richard, Vissat, Ludovica Luisa, Koopman, James S, and Simon, Carl P

Subjects
Immunization, Prevention, Genetics, Vaccine Related, Infection, Good Health and Well Being, COVID-19, Genetic Drift, Humans, Pandemics, SARS-CoV-2, Vaccination, SEIR individual-based models, escape mutations, RAMPs, pathogen variants, vaccination, General Science & Technology
Abstract

We present methods for building a Java Runtime-Alterable-Model Platform (RAMP) of complex dynamical systems. We illustrate our methods by building a multivariant SEIR (epidemic) RAMP. Underlying our RAMP is an individual-based model that includes adaptive contact rates, pathogen genetic drift, waning and cross-immunity. Besides allowing parameter values, process descriptions and scriptable runtime drivers to be easily modified during simulations, our RAMP can used within R-Studio and other computational platforms. Process descriptions that can be runtime altered within our SEIR RAMP include pathogen variant-dependent host shedding, environmental persistence, host transmission and within-host pathogen mutation and replication. They also include adaptive social distancing and adaptive application of vaccination rates and variant-valency of vaccines. We present simulation results using parameter values and process descriptions relevant to the current COVID-19 pandemic. Our results suggest that if waning immunity outpaces vaccination rates, then vaccination rollouts may fail to contain the most transmissible variants, particularly if vaccine valencies are not adapted to deal with escape mutations. Our SEIR RAMP is designed for easy use by others. More generally, our RAMP concept facilitates construction of highly flexible complex systems models of all types, which can then be easily shared as stand-alone application programs.

Published
2021

11. Modeling the population effects of epitope specific escape mutations in SARS-CoV-2 to guide vaccination strategies

Author

Koopman, James S, Simon, Carl P, Getz, Wayne M, and Salter, Richard

Subjects
Medical Microbiology, Biomedical and Clinical Sciences, Immunology, Emerging Infectious Diseases, Bioengineering, Immunization, Biotechnology, Biodefense, Prevention, Infectious Diseases, Vaccine Related, Infection, Good Health and Well Being
Abstract

Escape mutations (EM) to SARS-Cov-2 have been detected and are spreading. Vaccines may need adjustment to respond to these or future mutations. We designed a population level model integrating both waning immunity and EM. We also designed a set of criteria for elaborating and fitting this model to cross-neutralization and other data in a manner that minimizes vaccine decision errors. We formulated four model variations. These define criteria for which prior infections provide immunity that can be escaped. They also specify different sequences where one EM follows another. At all reasonable parameter values, these model variations led to patterns where: 1) EM were rare in the first epidemic, 2) rebound epidemics after the first epidemic were accelerated more by increasing drifting than by increasing waning (with some exceptions), 3) the long term endemic level of infection was determined mostly by waning rates with small effects of the drifting parameter, 4) EM caused loss of vaccine effectiveness and under some conditions, vaccines induced EM that caused higher levels of infection with vaccines than without them. The differences and similarities across the four models suggest paths for developing models specifying the epitopes where EM act. This model is a base on which to construct epitope specific evolutionary models using new high-throughput assay data from population samples to guide vaccine decisions. Highlights This model is the first to integrate both antigenic drifting from escape mutations and immunity waning in continuous time. Tiny amounts of only waning or only escape mutation drifting have small or no effects. Together, they have large effects. There are no or few escape mutations during the first epidemic peak and no effect of drifting parameters on the size of that wave. After the first epidemic peak, escape mutations accumulate rapidly. They increase with increases in waning rates and with increases in the drifting rate. Escape mutations then amplify other escape mutations since these raise the frequency of reinfections. Escape mutations can completely negate the effects of vaccines and even lead to more infections with vaccination than without, especially at very low waning rates. The model generates population level cross-neutralization patterns that enable the model to be fitted to population level serological data. The model can be modified to use laboratory data that determine the epitope specific effects of mutations on ACE2 attachment strength or escape from antibody effects. The model, although currently unable to predict the effects of escape mutations in the real world, opens up a path that can guide model incorporation of molecularly studied escape mutations and improve predictive value. We describe that path. Model analysis indicates that vaccine trials and serological surveys are needed now to detect the effects of epitope specific escape mutations that could cause the loss of vaccine efficacy.

Published
2021

17. Impact of Intracranial Volume and Brain Volume on the Prognostic Value of Computed Tomography Perfusion Core Volume in Acute Ischemic Stroke

Author

Hoving, Jan W., primary, Konduri, Praneeta R., additional, Tolhuisen, Manon L., additional, Koopman, Miou S., additional, van Voorst, Henk, additional, Van Poppel, Laura M., additional, Daems, Jasper D., additional, van Es, Adriaan C. G. M., additional, van Walderveen, Marianne A. A., additional, Lingsma, Hester F., additional, Dippel, Diederik W. J., additional, Van Zwam, Wim H., additional, Marquering, Henk A., additional, Majoie, Charles B. L. M., additional, and Emmer, Bart J., additional

Published
2024
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21. Costs and health effects of CT perfusion-based selection for endovascular thrombectomy within 6 hours of stroke onset: a model-based health economic evaluation.

Author

van Voorst, Henk, Hoving, Jan W., Koopman, Miou S., Daems, Jasper D., Peerlings, Daan, Buskens, Erik, Lingsma, Hester, Marquering, Henk A., de Jong, Hugo W. A. M., Berkhemer, Olvert A., van Zwam, Wim H., van Walderveen, Marianne A. A., van den Wijngaard, Ido R., Dippel, Diederik W. J., Yoo, Albert J., Campbell, Bruce, Kunz, Wolfgang G., Majoie, Charles B., and Emmer, Bart J.

Subjects
ENDOVASCULAR surgery, STROKE, ACADEMIC medical centers
Published
2024
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30. Prehospital Detection of Large Vessel Occlusion Stroke With Electroencephalography: Results of the ELECTRA-STROKE Study

Author

van Stigt, Maritta N, primary, Groenendijk, Eva A, additional, Van Meenen, Laura C, additional, van de Munckhof, Anita, additional, Theunissen, Monique, additional, Franschman, Gaby, additional, Smeekes, Martin D, additional, van Grondelle, Joffry A, additional, Geuzebroek, Geertje, additional, Siegers, Arjen, additional, Visser, Marieke C, additional, van Schaik, Sander M, additional, Halkes, Patricia H.A., additional, Majoie, Charles B, additional, Roos, Yvo B.W.M., additional, Koelman, Johannes H, additional, Koopman, Miou S, additional, Marquering, Henk, additional, Potters, Wouter V, additional, and Coutinho, Jonathan M., additional

Published
2023
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35. Individualized Aerobic Exercise in Neuromuscular Diseases: A Pilot Study on the Feasibility and Preliminary Effectiveness to Improve Physical Fitness

Author

Voorn, Eric L., Koopman, Fieke S., Nollet, Frans, and Brehm, Merel-Anne

Subjects
Neuromuscular diseases -- Care and treatment, Aerobic exercises -- Methods -- Health aspects, Exercise therapy -- Testing, Health
Abstract

Objective. Clear guidelines to prescribe aerobic exercise in neuromuscular diseases (NMD) are lacking, which hampers effective application in neuromuscular rehabilitation. This pilot study evaluated the feasibility and preliminary effectiveness of an individualized aerobic exercise program according to a recently developed training guide (B-FIT) to improve physical fitness in individuals with NMD. Methods. Thirty-one individuals who were ambulatory and had 15 different slowly progressive NMD participated in a 4-month, polarized, home-based, aerobic exercise program. The program included 2 low-intensity sessions and 1 high-intensity session per week. Feasibility outcomes were the following: completion rate, proportion of followed sessions, adverse events, and participant and therapist satisfaction based on a self-designed questionnaire. Submaximal incremental exercise tests were used to assess the effects on physical fitness. Results. Twenty-six participants (84%) completed the B-FIT program, and the proportion of followed sessions was >75%>. Three adverse events were reported and resolved. Regarding satisfaction, participants (based on n = 9) reported feeling fitter, but training was considered insufficiently challenging. Physical therapists (n = 5) reported that B-FIT provides a clear, well-grounded guidance. They perceived the time investment for initiating the program and the carry-over to primary care as the main barriers. The mean (SD) submaximal heart rate (based on n = 20) reduced significantly by -6.5 beats per minute (95% CI = -11.8 to -1.2), from 121.7 (16.5) at baseline to 115.2 (14.3) after intervention. Submaximal ratings of perceived exertion, anaerobic threshold, and peak workload also improved significantly (P < .05). Conclusion. The outcomes of this pilot study suggest that individualized aerobic exercise according to B-FIT is feasible and has potential to improve physical fitness in a wide variety of slowly progressive NMD. However, some barriers must be addressed before investigating the efficacy in a randomized controlled trial. Impact. The outcomes of this study demonstrate the feasibility of individualized aerobic exercise according to the B-FIT training guide and the potential to improve physical fitness in NMD. Physical therapists indicated that the use of B-FIT provides a clear, well-grounded guidance. The training guide can support health care professionals in the application of aerobic exercise in adult neuromuscular rehabilitation. Lay Summary. Individualized exercise according to the B-FIT training guide is feasible in a wide variety of slowly progressive NMD and might help improve physical fitness. Keywords: Aerobic Exercise, Neuromuscular Diseases, Feasibility, Rehabilitation, Physical Fitness, Introduction Physical inactivity is a common problem in individuals with neuromuscular diseases (NMD) and is caused by symptoms of muscle weakness, fatigue, and pain. (1-3) Inactivity leads to reduced physical [...]

Published
2021
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43. Accuracy of Four Different CT Perfusion Thresholds for Ischemic Core Volume and Location Estimation Using IntelliSpace Portal

Author

Koopman, Miou S., primary, Hoving, Jan W., additional, Tolhuisen, Manon L., additional, Jin, Peng, additional, Thiele, Frank O., additional, Bremer-van der Heiden, Linda, additional, van Voorst, Henk, additional, Berkhemer, Olvert A., additional, Coutinho, Jonathan M., additional, Beenen, Ludo F. M., additional, Marquering, Henk A., additional, Emmer, Bart J., additional, and Majoie, Charles B. L. M., additional

Published
2023
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