104 results on '"Conway, Jessica"'
Search Results
2. Assessing the impact of autologous virus neutralizing antibodies on viral rebound time in postnatally SHIV-infected ART-treated infant rhesus macaques
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Mainou, Ellie, Berendam, Stella J., Obregon-Perko, Veronica, Uffman, Emilie A., Phan, Caroline T., Shaw, George M., Bar, Katharine J., Kumar, Mithra R., Fray, Emily J., Siliciano, Janet M., Siliciano, Robert F., Silvestri, Guido, Permar, Sallie R., Fouda, Genevieve G., McCarthy, Janice, Chahroudi, Ann, Conway, Jessica M., and Chan, Cliburn
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- 2024
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3. The role of day-respite centres in supporting people with dementia to age in place: An interpretive phenomenological study
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Lole, Lisa, Conway, Jessica, Oorloff, Anthea, and Duffy, Cameron
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- 2023
4. Comparing dosimetry of locally advanced cervical cancer patients treated with 3 versus 4 fractions of MRI-guided brachytherapy
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Scott, Aba Anoa, Weersink, Madrigal, Liu, Zhihui Amy, Milosevic, Michael, Croke, Jennifer, Fyles, Anthony, Lukovic, Jelena, Rink, Alexandra, Beiki-Ardakani, Akbar, Borg, Jette, Xie, Jason, Chan, Kitty, Ballantyne, Heather, Skliarenko, Julia, Conway, Jessica L., Gladwish, Adam, Weersink, Robert A., and Han, Kathy
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- 2023
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5. Comparison between frail and non-frail older adults’ gut microbiota: A systematic review and meta-analysis
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Almeida, Helena Maia, Sardeli, Amanda V., Conway, Jessica, Duggal, Niharika Arora, and Cavaglieri, Cláudia Regina
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- 2022
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6. Water transport regulates nucleus volume, cell density, Young’s modulus, and E-cadherin expression in tumor spheroids
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Conrad, Christina, Conway, Jessica, Polacheck, William J., Rizvi, Imran, and Scarcelli, Giuliano
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- 2022
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7. Age‐related loss of intestinal barrier integrity plays an integral role in thymic involution and T cell ageing.
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Conway, Jessica, De Jong, Erica N., White, Andrea J., Dugan, Ben, Rees, Nia Paddison, Parnell, Sonia M., Lamberte, Lisa E., Sharma‐Oates, Archana, Sullivan, Jack, Mauro, Claudio, Schaik, Willem, Anderson, Graham, Bowdish, Dawn M. E., and Duggal, Niharika A.
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REGULATORY T cells , *T-cell exhaustion , *INTESTINAL barrier function , *CELLULAR aging , *INTESTINAL mucosa , *IMMUNOSENESCENCE , *T cells - Abstract
The intestinal epithelium serves as a physical and functional barrier against harmful substances, preventing their entry into the circulation and subsequent induction of a systemic immune response. Gut barrier dysfunction has recently emerged as a feature of ageing linked to declining health, and increased intestinal membrane permeability has been shown to promote heightened systemic inflammation in aged hosts. Concurrent with age‐related changes in the gut microbiome, the thymic microenvironment undergoes a series of morphological, phenotypical and architectural alterations with age, including disorganisation of the corticomedullary junction, increased fibrosis, increased thymic adiposity and the accumulation of senescent cells. However, a direct link between gut barrier dysbiosis and thymic involution leading to features of immune ageing has not been explored thus far. Herein, we reveal strong associations between enhanced microbial translocation and the peripheral accumulation of terminally differentiated, senescent and exhausted T cells and the compensatory expansion of regulatory T cells in older adults. Crucially, we demonstrate that aged germ‐free mice are protected from age‐related increases in intestinal permeability, highlighting the direct impact of mucosal permeability on thymic ageing. Together, these findings establish a novel mechanism by which gut barrier dysfunction drives systemic activation of the immune system during ageing through thymic involution. This enhances our understanding of drivers of T cell ageing and opens up the possibility for the use of microbiome‐based interventions to restore immune homeostasis and promote healthy ageing in older adults. [ABSTRACT FROM AUTHOR]
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- 2024
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8. Gene targeting techniques for Huntington’s disease
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Fields, Eric, Vaughan, Erik, Tripu, Deepika, Lim, Isabelle, Shrout, Katherine, Conway, Jessica, Salib, Nicole, Lee, Yubin, Dhamsania, Akash, Jacobsen, Michael, Woo, Ashley, Xue, Huijing, and Cao, Kan
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- 2021
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9. Ageing of the gut microbiome: Potential influences on immune senescence and inflammageing
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Conway, Jessica and A Duggal, Niharika
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- 2021
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10. Clinical Evaluation of Deep Learning and Atlas-Based Auto-Contouring of Bladder and Rectum for Prostate Radiation Therapy
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Zabel, W. Jeffrey, Conway, Jessica L., Gladwish, Adam, Skliarenko, Julia, Didiodato, Giulio, Goorts-Matthews, Leah, Michalak, Adam, Reistetter, Sarah, King, Jenna, Nakonechny, Keith, Malkoske, Kyle, Tran, Muoi N., and McVicar, Nevin
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- 2021
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11. Understanding early HIV-1 rebound dynamics following antiretroviral therapy interruption: The importance of effector cell expansion.
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Phan, Tin, Conway, Jessica M., Pagane, Nicole, Kreig, Jasmine, Sambaturu, Narmada, Iyaniwura, Sarafa, Li, Jonathan Z., Ribeiro, Ruy M., Ke, Ruian, and Perelson, Alan S.
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HIV , *ANTIRETROVIRAL agents , *VIRAL load , *DYNAMIC models - Abstract
Most people living with HIV-1 experience rapid viral rebound once antiretroviral therapy is interrupted; however, a small fraction remain in viral remission for an extended duration. Understanding the factors that determine whether viral rebound is likely after treatment interruption can enable the development of optimal treatment regimens and therapeutic interventions to potentially achieve a functional cure for HIV-1. We built upon the theoretical framework proposed by Conway and Perelson to construct dynamic models of virus-immune interactions to study factors that influence viral rebound dynamics. We evaluated these models using viral load data from 24 individuals following antiretroviral therapy interruption. The best-performing model accurately captures the heterogeneity of viral dynamics and highlights the importance of the effector cell expansion rate. Our results show that post-treatment controllers and non-controllers can be distinguished based on the effector cell expansion rate in our models. Furthermore, these results demonstrate the potential of using dynamic models incorporating an effector cell response to understand early viral rebound dynamics post-antiretroviral therapy interruption. Author summary: Most people living with HIV-1 experience rapid viral rebound once antiretroviral therapy is interrupted; however, a small fraction remain in viral remission for an extended duration. The factors that determine viral rebound dynamics after treatment interruption are not well understood. In this study, we built upon a previous theoretical framework to construct dynamic models of virus-immune interactions to study factors that influence viral rebound dynamics. We evaluated these models using viral load data from 24 individuals following antiretroviral therapy interruption. The best-performing model accurately captures the heterogeneity of viral dynamics and robustly shows that people who remain in viral remission for an extended duration after treatment interruption have a higher effector cell expansion rate compared to those who rapidly rebound. These results demonstrate the potential of using viral dynamic models incorporating an effector cell response to understand early viral rebound dynamics post-antiretroviral therapy interruption. [ABSTRACT FROM AUTHOR]
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- 2024
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12. Long-term patient-reported distress in locally advanced cervical cancer patients treated with definitive chemoradiation
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Conway, Jessica L., Felder, Shira, Tang, Jiayin, Lukovic, Jelena, Han, Kathy, Liu, Zhihui, Milosevic, Michael, Fyles, Anthony, and Croke, Jennifer
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- 2020
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13. Repeatability and reproducibility of MRI-based radiomic features in cervical cancer
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Fiset, Sandra, Welch, Mattea L., Weiss, Jessica, Pintilie, Melania, Conway, Jessica L., Milosevic, Michael, Fyles, Anthony, Traverso, Alberto, Jaffray, David, Metser, Ur, Xie, Jason, and Han, Kathy
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- 2019
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14. Patient-reported sexual adjustment after definitive chemoradiation and MR-guided brachytherapy for cervical cancer
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Conway, Jessica L., Gerber, Rachel, Han, Kathy, Jiang, Haiyan, Xie, Jason, Beiki-Ardakani, Akbar, Fyles, Anthony, Milosevic, Michael, Williamson, Deborah, and Croke, Jennifer
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- 2019
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15. Modeling dynamics of acute HIV infection incorporating density-dependent cell death and multiplicity of infection.
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Mainou, Ellie, Ribeiro, Ruy M., and Conway, Jessica M.
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HIV infections ,CELL death ,AKAIKE information criterion ,VIRAL load ,HIV-positive persons - Abstract
Understanding the dynamics of acute HIV infection can offer valuable insights into the early stages of viral behavior, potentially helping uncover various aspects of HIV pathogenesis. The standard viral dynamics model explains HIV viral dynamics during acute infection reasonably well. However, the model makes simplifying assumptions, neglecting some aspects of HIV infection. For instance, in the standard model, target cells are infected by a single HIV virion. Yet, cellular multiplicity of infection (MOI) may have considerable effects in pathogenesis and viral evolution. Further, when using the standard model, we take constant infected cell death rates, simplifying the dynamic immune responses. Here, we use four models—1) the standard viral dynamics model, 2) an alternate model incorporating cellular MOI, 3) a model assuming density-dependent death rate of infected cells and 4) a model combining (2) and (3)—to investigate acute infection dynamics in 43 people living with HIV very early after HIV exposure. We find that all models qualitatively describe the data, but none of the tested models is by itself the best to capture different kinds of heterogeneity. Instead, different models describe differing features of the dynamics more accurately. For example, while the standard viral dynamics model may be the most parsimonious across study participants by the corrected Akaike Information Criterion (AICc), we find that viral peaks are better explained by a model allowing for cellular MOI, using a linear regression analysis as analyzed by R
2 . These results suggest that heterogeneity in within-host viral dynamics cannot be captured by a single model. Depending on the specific aspect of interest, a corresponding model should be employed. Author summary: We conducted a study to better understand the dynamics of early HIV-1 infection using four different mathematical models. These models tested various biological hypotheses, including the presence of cellular coinfection and phenomenological model capturing aspects of immune responses. We analyzed viral load data from 43 participants in a rich dataset of people recently infected. The models we used were the standard viral dynamics model, a model incorporating density-dependent cell death of infected cells, a model with coinfection of infected cells (an adaptation of a macroparasite model to HIV-1 dynamics), and a model that combined cellular coinfection and density-dependent cell death. Overall, the model incorporating density-dependent cell death of infected cells performed the best according to the Akaike Information Criterion (AIC) and Bayesian Information Criterion (BIC). We also assessed the models' performance by comparing them based on measures such as viral growth rate, peak magnitude and timing, decay rate, and setpoint. We find that different models describe differing features of the dynamics more accurately. For example, viral peaks are better explained by a model allowing for cellular multiplicity of infection (MOI). These results suggest that heterogeneity in within-host viral dynamics cannot be captured by a single model. Therefore, depending on the aspect of interest, a corresponding appropriate model should be employed. [ABSTRACT FROM AUTHOR]- Published
- 2024
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16. Incorporating Intracellular Processes in Virus Dynamics Models.
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Ciupe, Stanca M. and Conway, Jessica M.
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LIFE cycles (Biology) ,VIRUS diseases ,ACQUISITION of data ,PREDICTION models - Abstract
In-host models have been essential for understanding the dynamics of virus infection inside an infected individual. When used together with biological data, they provide insight into viral life cycle, intracellular and cellular virus–host interactions, and the role, efficacy, and mode of action of therapeutics. In this review, we present the standard model of virus dynamics and highlight situations where added model complexity accounting for intracellular processes is needed. We present several examples from acute and chronic viral infections where such inclusion in explicit and implicit manner has led to improvement in parameter estimates, unification of conclusions, guidance for targeted therapeutics, and crossover among model systems. We also discuss trade-offs between model realism and predictive power and highlight the need of increased data collection at finer scale of resolution to better validate complex models. [ABSTRACT FROM AUTHOR]
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- 2024
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17. EARLY HIV INFECTION PREDICTIONS: ROLE OF VIRAL REPLICATION ERRORS
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CONWAY, JESSICA M. and PERELSON, ALAN S.
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- 2018
18. Modeling the immune response to HIV infection
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Conway, Jessica M. and Ribeiro, Ruy M.
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- 2018
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19. Deep inspiration breath hold level variability and deformation in locoregional breast irradiation
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Conroy, Leigh, Quirk, Sarah, Watt, Elizabeth, Ecclestone, Gillian, Conway, Jessica L., Olivotto, Ivo A., Phan, Tien, and Smith, Wendy L.
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- 2018
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20. On the duration of the period between exposure to HIV and detectable infection
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Konrad, Bernhard P., Taylor, Darlene, Conway, Jessica M., Ogilvie, Gina S., and Coombs, Daniel
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- 2017
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21. Deep inspiration breath-hold produces a clinically meaningful reduction in ipsilateral lung dose during locoregional radiation therapy for some women with right-sided breast cancer
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Conway, Jessica L., Conroy, Leigh, Harper, Lindsay, Scheifele, Marie, Li, Haocheng, Smith, Wendy L., Graham, Tannis, Phan, Tien, and Olivotto, Ivo A.
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- 2017
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22. Comparison of patient-reported outcomes with single versus multiple fraction palliative radiotherapy for bone metastasis in a population-based cohort
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Conway, Jessica L., Yurkowski, Emily, Glazier, Justin, Gentles, Quinn, Walter, Allison, Bowering, Gale, Curtis, Susan, Schellenberg, Devin, Halperin, Ross, Lapointe, Vincent, Beckham, Wayne, Olivotto, Ivo A., and Olson, Robert Anton
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- 2016
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23. Clinical Outcomes of Surgically Unresectable Endometrial Cancers
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Conway, Jessica L., Lukovic, Jelena, Ferguson, Sarah E., Zhang, Jiahui, Xu, Wei, Dhani, Neesha, Croke, Jennifer, Fyles, Anthony, Milosevic, Michael, Rink, Alexandra, Rouzbahman, Marjan, and Han, Kathy
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- 2019
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24. The role of sleep quality and quantity in moderating the effectiveness of medication in the treatment of children with ADHD
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Morash-Conway, Jessica, Gendron, Melissa, and Corkum, Penny
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- 2017
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25. Post-treatment control of HIV infection
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Conway, Jessica M. and Perelson, Alan S.
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- 2015
26. STOCHASTIC ANALYSIS OF PRE- AND POSTEXPOSURE PROPHYLAXIS AGAINST HIV INFECTION
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CONWAY, JESSICA M., KONRAD, BERNHARD P., and COOMBS, DANIEL
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- 2013
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27. Fast-Training Deep Learning Algorithm for Multiplex Quantification of Mammalian Bioproduction Metabolites via Contactless Short-Wave Infrared Hyperspectral Sensing.
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Hevaganinge, Anjana, Weber, Callie M., Filatova, Anna, Musser, Amy, Neri, Anthony, Conway, Jessica, Yuan, Yiding, Cattaneo, Maurizio, Clyne, Alisa Morss, and Tao, Yang
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- 2023
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28. Inflammaging as a target for healthy ageing.
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Dugan, Ben, Conway, Jessica, and Duggal, Niharika A
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INFLAMMATION treatment , *PREVENTION of chronic diseases , *THERAPEUTIC use of probiotics , *THERAPEUTICS , *STATINS (Cardiovascular agents) , *ACTIVE aging , *LIFE expectancy , *PROTEIN kinase inhibitors , *DIET therapy , *DIETARY supplements , *PHYTOCHEMICALS , *HEALTH behavior , *QUALITY of life , *EXERCISE , *LONGEVITY , *MITOGEN-activated protein kinases , *BEHAVIOR modification , *OLD age - Abstract
Life expectancy has been on the rise for the past few decades, but healthy life expectancy has not kept pace, leading to a global burden of age-associated disorders. Advancing age is accompanied by a chronic increase in basal systemic inflammation, termed inflammaging, contributing towards an increased risk of developing chronic diseases in old age. This article reviews the recent literature to formulate hypotheses regarding how age-associated inflammaging plays a crucial role in driving chronic diseases and ill health in older adults. Here, we discuss how non-pharmacological intervention strategies (diet, nutraceutical supplements, phytochemicals, physical activity, microbiome-based therapies) targeting inflammaging restore health in older adults. We also consider alternative existing pharmacological interventions (Caloric restriction mimetics, p38 mitogen-activated protein kinase inhibitors) and explore novel targets (senolytics) aimed at combating inflammaging and optimising the ageing process to increase healthy lifespan. [ABSTRACT FROM AUTHOR]
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- 2023
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29. Understanding the role of host metabolites in the induction of immune senescence: Future strategies for keeping the ageing population healthy.
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Conway, Jessica, Certo, Michelangelo, Lord, Janet M., Mauro, Claudio, and Duggal, Niharika A.
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Advancing age is accompanied by significant remodelling of the immune system, termed immune senescence, and increased systemic inflammation, termed inflammageing, both of which contribute towards an increased risk of developing chronic diseases in old age. Age‐associated alterations in metabolic homeostasis have been linked with changes in a range of physiological functions, but their effects on immune senescence remains poorly understood. In this article, we review the recent literature to formulate hypotheses as to how an age‐associated dysfunctional metabolism, driven by an accumulation of key host metabolites (saturated fatty acids, cholesterol, ceramides and lactate) and loss of other metabolites (glutamine, tryptophan and short‐chain fatty acids), might play a role in driving immune senescence and inflammageing, ultimately leading to diseases of old age. We also highlight the potential use of metabolic immunotherapeutic strategies targeting these processes in counteracting immune senescence and restoring immune homeostasis in older adults. LINKED ARTICLES: This article is part of a themed issue on Inflammation, Repair and Ageing. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v179.9/issuetoc [ABSTRACT FROM AUTHOR]
- Published
- 2022
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30. Viral Load Kinetics of Severe Acute Respiratory Syndrome Coronavirus 2 in Hospitalized Individuals With Coronavirus Disease 2019.
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Regan, James, Flynn, James P, Rosenthal, Alexandra, Jordan, Hannah, Li, Yijia, Chishti, Rida, Giguel, Francoise, Corry, Heather, Coxen, Kendyll, Fajnzylber, Jesse, Gillespie, Elizabeth, Kuritzkes, Daniel R, Hacohen, Nir, Goldberg, Marcia B, Filbin, Michael R, Yu, Xu G, Baden, Lindsey, Ribeiro, Ruy M, Perelson, Alan S, and Conway, Jessica M
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COVID-19 ,VIRAL load ,SARS-CoV-2 ,REMDESIVIR ,SYMPTOMS - Abstract
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) kinetics remain understudied, including the impact of remdesivir. In hospitalized individuals, peak sputum viral load occurred in week 2 of symptoms, whereas viremia peaked within 1 week of symptom-onset, suggesting early systemic seeding of SARS-CoV-2. Remdesivir treatment was associated with faster viral decay. [ABSTRACT FROM AUTHOR]
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- 2021
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31. Vaccination against 2009 pandemic H1N1 in a population dynamical model of Vancouver, Canada: timing is everything
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Conway Jessica M, Tuite Ashleigh R, Fisman David N, Hupert Nathaniel, Meza Rafael, Davoudi Bahman, English Krista, van den Driessche P, Brauer Fred, Ma Junling, Meyers Lauren Ancel, Smieja Marek, Greer Amy, Skowronski Danuta M, Buckeridge David L, Kwong Jeffrey C, Wu Jianhong, Moghadas Seyed M, Coombs Daniel, Brunham Robert C, and Pourbohloul Babak
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Public aspects of medicine ,RA1-1270 - Abstract
Abstract Background Much remains unknown about the effect of timing and prioritization of vaccination against pandemic (pH1N1) 2009 virus on health outcomes. We adapted a city-level contact network model to study different campaigns on influenza morbidity and mortality. Methods We modeled different distribution strategies initiated between July and November 2009 using a compartmental epidemic model that includes age structure and transmission network dynamics. The model represents the Greater Vancouver Regional District, a major North American city and surrounding suburbs with a population of 2 million, and is parameterized using data from the British Columbia Ministry of Health, published studies, and expert opinion. Outcomes are expressed as the number of infections and deaths averted due to vaccination. Results The model output was consistent with provincial surveillance data. Assuming a basic reproduction number = 1.4, an 8-week vaccination campaign initiated 2 weeks before the epidemic onset reduced morbidity and mortality by 79-91% and 80-87%, respectively, compared to no vaccination. Prioritizing children and parents for vaccination may have reduced transmission compared to actual practice, but the mortality benefit of this strategy appears highly sensitive to campaign timing. Modeling the actual late October start date resulted in modest reductions in morbidity and mortality (13-25% and 16-20%, respectively) with little variation by prioritization scheme. Conclusion Delays in vaccine production due to technological or logistical barriers may reduce potential benefits of vaccination for pandemic influenza, and these temporal effects can outweigh any additional theoretical benefits from population targeting. Careful modeling may provide decision makers with estimates of these effects before the epidemic peak to guide production goals and inform policy. Integration of real-time surveillance data with mathematical models holds the promise of enabling public health planners to optimize the community benefits from proposed interventions before the pandemic peak.
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- 2011
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32. Models of SIV rebound after treatment interruption that involve multiple reactivation events.
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van Dorp, Christiaan H., Conway, Jessica M., Barouch, Dan H., Whitney, James B., and Perelson, Alan S.
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SIMIAN immunodeficiency virus , *TREATMENT effectiveness , *VIRAL load , *EXPONENTIAL functions , *INFERENTIAL statistics , *ANTIRETROVIRAL agents , *GROWTH curves (Statistics) , *STRUCTURED treatment interruption - Abstract
In order to assess the efficacy of novel HIV-1 treatments leading to a functional cure, the time to viral rebound is frequently used as a surrogate endpoint. The longer the time to viral rebound, the more efficacious the therapy. In support of such an approach, mathematical models serve as a connection between the size of the latent reservoir and the time to HIV-1 rebound after treatment interruption. The simplest of such models assumes that a single successful latent cell reactivation event leads to observable viremia after a period of exponential viral growth. Here we consider a generalization developed by Pinkevych et al. and Hill et al. of this simple model in which multiple reactivation events can occur, each contributing to the exponential growth of the viral load. We formalize and improve the previous derivation of the dynamics predicted by this model, and use the model to estimate relevant biological parameters from SIV rebound data. We confirm a previously described effect of very early antiretroviral therapy (ART) initiation on the rate of recrudescence and the viral load growth rate after treatment interruption. We find that every day ART initiation is delayed results in a 39% increase in the recrudescence rate (95% credible interval: [18%, 62%]), and a 11% decrease of the viral growth rate (95% credible interval: [4%, 20%]). We show that when viral rebound occurs early relative to the viral load doubling time, a model with multiple successful reactivation events fits the data better than a model with only a single successful reactivation event. Author summary: HIV-1 persists during suppressive antiretroviral therapy (ART) due to a reservoir of latently infected cells. When ART is stopped, HIV generally rebounds within a few weeks. However, there is a small fraction of patients that do not rebound over a period of months or years. A variety of treatments are being tested for their ability to reduce the size of the latent reservoir, to induce effective immune responses against the virus, or to prevent or prolong the time to viral rebound after ART interruption. These novel treatments are typically first tested in SIV infected macaques, and the efficacy of the treatment assessed by interrupting ART and measuring the time to viral rebound. Here, we develop and test a mathematical and statistical model that describes the process of viral rebound. The model can be used for statistical inference of the efficacy of newly developed treatments. Importantly, the model takes into account that multiple recrudescence events can precede rebound. We test the model using data from early treated SIV infected macaques. [ABSTRACT FROM AUTHOR]
- Published
- 2020
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33. Predictions of time to HIV viral rebound following ART suspension that incorporate personal biomarkers.
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Conway, Jessica M., Perelson, Alan S., and Li, Jonathan Z.
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HIV infections , *HIV , *VIRAL load , *THERAPEUTICS , *PHYSICAL sciences , *HIV infection transmission - Abstract
Antiretroviral therapy (ART) effectively controls HIV infection, suppressing HIV viral loads. Suspension of therapy is followed by rebound of viral loads to high, pre-therapy levels. However, there is significant heterogeneity in speed of rebound, with some rebounds occurring within days, weeks, or sometimes years. We present a stochastic mathematical model to gain insight into these post-treatment dynamics, specifically characterizing the dynamics of short term viral rebounds (≤ 60 days). Li et al. (2016) report that the size of the expressed HIV reservoir, i.e., cell-associated HIV RNA levels, and drug regimen correlate with the time between ART suspension and viral rebound to detectable levels. We incorporate this information and viral rebound times to parametrize our model. We then investigate insights offered by our model into the underlying dynamics of the latent reservoir. In particular, we refine previous estimates of viral recrudescence after ART interruption by accounting for heterogeneity in infection rebound dynamics, and determine a recrudescence rate of once every 2-4 days. Our parametrized model can be used to aid in design of clinical trials to study viral dynamics following analytic treatment interruption. We show how to derive informative personalized testing frequencies from our model and offer a proof-of-concept example. Our results represent first steps towards a model that can make predictions on a person living with HIV (PLWH)’s rebound time distribution based on biomarkers, and help identify PLWH with long viral rebound delays. [ABSTRACT FROM AUTHOR]
- Published
- 2019
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34. Sleep in Offspring of Parents With Mood Disorders.
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Wescott, Delainey L., Morash-Conway, Jessica, Zwicker, Alyson, Cumby, Jill, Uher, Rudolf, and Rusak, Benjamin
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AFFECTIVE disorders ,BIPOLAR disorder ,MENTAL illness ,PSYCHIATRIC diagnosis ,ACTIGRAPHY - Abstract
Background: Sleep problems in childhood are an early predictor of mood disorders among individuals at high familial risk. However, the majority of the research has focused on sleep disturbances in already diagnosed individuals and has largely neglected investigating potential differences between weeknight and weekend sleep in high-risk offspring. This study examined sleep parameters in offspring of parents with major depressive disorder or bipolar disorder during both weeknights and weekends. Methods: We used actigraphy, sleep diaries, and questionnaires to measure several sleep characteristics in 73 offspring aged 4–19 years: 23 offspring of a parent with major depressive disorder, 22 offspring of a parent with bipolar disorder, and 28 control offspring. Results: Offspring of parents with major depressive disorder slept, on average, 26 min more than control offspring on weeknights (95% confidence interval, 3 to 49 min, p = 0.027). Offspring of parents with bipolar disorder slept, on average, 27 min more on weekends than on weeknights compared to controls, resulting in a significant family history × weekend interaction (95% confidence interval, 7 to 47 min, p = 0.008). Conclusions: Sleep patterns in children and adolescents were related to the psychiatric diagnosis of their parent(s). Future follow-up of these results may clarify the relations between early sleep differences and the risk of developing mood disorders in individuals at high familial risk. [ABSTRACT FROM AUTHOR]
- Published
- 2019
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35. Clinical implementation of AXB from AAA for breast: Plan quality and subvolume analysis.
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Guebert, Alexandra, Conroy, Leigh, Weppler, Sarah, Alghamdi, Majed, Conway, Jessica, Harper, Lindsay, Phan, Tien, Olivotto, Ivo A., Smith, Wendy L., and Quirk, Sarah
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RADIOTHERAPY treatment planning ,BREAST cancer treatment ,RADIATION doses ,IMAGE quality analysis ,CLINICAL trials - Abstract
Abstract: Purpose: Two dose calculation algorithms are available in Varian Eclipse software: Anisotropic Analytical Algorithm (AAA) and Acuros External Beam (AXB). Many Varian Eclipse‐based centers have access to AXB; however, a thorough understanding of how it will affect plan characteristics and, subsequently, clinical practice is necessary prior to implementation. We characterized the difference in breast plan quality between AXB and AAA for dissemination to clinicians during implementation. Methods: Locoregional irradiation plans were created with AAA for 30 breast cancer patients with a prescription dose of 50 Gy to the breast and 45 Gy to the regional node, in 25 fractions. The internal mammary chain (IMC
CTV ) nodes were covered by 80% of the breast dose. AXB, both dose‐to‐water and dose‐to‐medium reporting, was used to recalculate plans while maintaining constant monitor units. Target coverage and organ‐at‐risk doses were compared between the two algorithms using dose–volume parameters. An analysis to assess location‐specific changes was performed by dividing the breast into nine subvolumes in the superior–inferior and left–right directions. Results: There were minimal differences found between the AXB and AAA calculated plans. The median difference between AXB and AAA for breastCTV V95% , was <2.5%. For IMCCTV , the median differences V95% , and V80% were <5% and 0%, respectively; indicating IMCCTV coverage only decreased when marginally covered. Mean superficial dose increased by a median of 3.2 Gy. In the subvolume analysis, the medial subvolumes were “hotter” when recalculated with AXB and the lateral subvolumes “cooler” with AXB; however, all differences were within 2 Gy. Conclusion: We observed minimal difference in magnitude and spatial distribution of dose when comparing the two algorithms. The largest observable differences occurred in superficial dose regions. Therefore, clinical implementation of AXB from AAA for breast radiotherapy is not expected to result in changes in clinical practice for prescribing or planning breast radiotherapy. [ABSTRACT FROM AUTHOR]- Published
- 2018
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36. A New Age-Structured Multiscale Model of the Hepatitis C Virus Life-Cycle During Infection and Therapy With Direct-Acting Antiviral Agents.
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Quintela, Barbara de M., Conway, Jessica M., Hyman, James M., Guedj, Jeremie, dos Santos, Rodrigo W., Lobosco, Marcelo, and Perelson, Alan S.
- Subjects
HEPATITIS C virus ,RIBOSOMAL DNA - Abstract
The dynamics of hepatitis C virus (HCV) RNA during translation and replication within infected cells were added to a previous age-structured multiscale mathematical model of HCV infection and treatment. The model allows the study of the dynamics of HCV RNA inside infected cells as well as the release of virus from infected cells and the dynamics of subsequent new cell infections. The model was used to fit in vitro data and estimate parameters characterizing HCV replication. This is the first model to our knowledge to consider both positive and negative strands of HCV RNA with an age-structured multiscale modeling approach. Using this model we also studied the effects of direct-acting antiviral agents (DAAs) in blocking HCV RNA intracellular replication and the release of new virions and fit the model to in vivo data obtained from HCV-infected subjects under therapy. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
- View/download PDF
37. Calcinosis cutis of the thumb.
- Author
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Hunter‐Dickson, Mitchell and Conway, Jessica
- Published
- 2023
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38. Optimizing phage λ survival in a changing environment: Stochastic model predictions.
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Conway, Jessica M., Dennehy, John J., and Singh, Abhyudai
- Published
- 2016
- Full Text
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39. 32: Setup and Treatment Efficiency of Two Prostate SBRT Rectal Preparation Techniques: Experience from Program Development at a Community Centre.
- Author
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Gladwish, Adam, Conway, Jessica, Stevens, Christiaan, Mclean, Jesse, Yoon, Fred, Lamb, Amanda, Tran, Muoi, Kim, Janice, and Quinn, Patrick
- Subjects
- *
COMMUNITY centers , *PROSTATE - Published
- 2022
- Full Text
- View/download PDF
40. Ingestion of Stingrays (Dasyatis spp.) by a Common Bottlenose Dolphin (Tursiops truncatus).
- Author
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Conway, Jessica N. and McFee, Wayne E.
- Subjects
- *
INGESTION , *STINGRAYS , *BOTTLENOSE dolphin , *FORAGING behavior - Abstract
The article discusses the case of ingestion of stingrays (Dasyatis spp.) by a common bottlenose dolphin (Tursiops truncatus) from the Atlantic Ocean. Topics include the presence of several parasitic cysts along the interior lining of the pyloric chamber, the association between the foraging behavior of the dolphin with a shrimp trawler, and the increase in likelihood of fatality due to stingray spine perforation.
- Published
- 2017
- Full Text
- View/download PDF
41. Disruptive mood dysregulation disorder in offspring of parents with depression and bipolar disorder.
- Author
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Propper, Lukas, Cumby, Jill, Patterson, Victoria C., Drobinin, Vladislav, Glover, Jacqueline M., MacKenzie, Lynn E., Morash-Conway, Jessica, Abidi, Sabina, Bagnell, Alexa, Lovas, David, Hajek, Tomas, Gardner, William, Pajer, Kathleen, Alda, Martin, and Uher, Rudolf
- Subjects
MENTAL depression risk factors ,CHILDREN of depressed persons ,MENTAL depression ,THERAPEUTICS ,BEHAVIOR disorders in children ,DEPRESSED persons ,PEOPLE with mental illness - Abstract
BackgroundIt has been suggested that offspring of parents with bipolar disorder are at increased risk for disruptive mood dysregulation disorder (DMDD), but the specificity of this association has not been established.AimsWe examined the specificity of DMDD to family history by comparing offspring of parents with (a) bipolar disorder, (b) major depressive disorder and (c) a control group with no mood disorders.MethodWe established lifetime diagnosis of DMDD using the Schedule for Affective Disorders and Schizophrenia for School Aged Children for DSM-5 in 180 youth aged 6-18 years, including 58 offspring of parents with bipolar disorder, 82 offspring of parents with major depressive disorder and 40 control offspring.ResultsDiagnostic criteria for DMDD were met in none of the offspring of parents with bipolar disorder, 6 of the offspring of parents with major depressive disorder and none of the control offspring. DMDD diagnosis was significantly associated with family history of major depressive disorder.ConclusionsOur results suggest that DMDD is not specifically associated with a family history of bipolar disorder and may be associated with parental depression. [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
- View/download PDF
42. The barriers and facilitators that indigenous health workers experience in their workplace and communities in providing self-management support: a multiple case study.
- Author
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Conway, Jessica, Tsourtos, George, and Lawn, Sharon
- Subjects
- *
INDIGENOUS peoples , *LIFE expectancy , *MEDICAL personnel , *AUSTRALIANS , *HEALTH planning - Abstract
Background: The inequality in health outcomes between Indigenous (Throughout the paper, the term Indigenous will be used to represent both Aboriginal Australians and Torres Strait Islander Australians.) and non-Indigenous Australians continues to be a major public health issue. Chronic conditions are responsible for the majority of the gap in life expectancy for this population. Evidence suggests that chronic condition management models focusing on self-management have led to improved health outcomes in Indigenous populations. The Flinders Closing the Gap Program (FCTGP) is a chronic condition care planning tool which aims to engage Indigenous people in self-managing their chronic conditions. Indigenous health workers (IHWs) can provide culturally appropriate self-management support; however there is paucity in current literature describing specific barriers and facilitators that they may experience when attempting to deliver this support. This study aimed to explore IHWs' perceptions of the effectiveness and appropriateness of the FCTGP, as an evidence-based example of self-management support, and to explore the barriers and facilitators that IHWs experience in their workplace and communities in providing self-management support.Methods: In-depth interviews were undertaken with five IHWs, drawn from five different states in Australia. Their selection was aided by key informants from the FCTGP training unit. Interviews were recorded and transcribed verbatim, and were analysed using thematic analysis.Results: The following themes were identified. IHWs reported that the FCTGP was appropriate, flexible and acceptable in their communities. Facilitators included factors improving client and worker empowerment, and activities around sharing knowledge. Barriers included competing priorities that clients experience relating to social determinants of health, and negative experiences within mainstream health services. IHW burnout from time pressures, lack of support, and high staff turnover were also considered important barriers.Conclusions: This study contributes an insight into the experiences of IHWs who are considered important stakeholders in implementation and sustainability of chronic condition management programs, including the FCTGP. Recommendations focus on supporting and supplementing the role of IHWs and identify the FCTGP as a facilitator in providing self-management support to a population with complex needs. [ABSTRACT FROM AUTHOR]- Published
- 2017
- Full Text
- View/download PDF
43. Secondary Breast Cancer Risk by Radiation Volume in Women With Hodgkin Lymphoma.
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Conway, Jessica L., Connors, Joseph M., Tyldesley, Scott, Savage, Kerry J., Campbell, Belinda A., Zheng, Yvonne Y., Hamm, Jeremy, and Pickles, Tom
- Subjects
- *
BREAST cancer , *RADIATION , *HODGKIN'S disease , *ANALYSIS of variance , *ANTINEOPLASTIC agents , *BENZAMIDE , *BREAST tumors , *CONFIDENCE intervals , *DATABASES , *CAUSES of death , *LONGITUDINAL method , *OVARIAN diseases , *PREDNISONE , *PREMATURE menopause , *RADIATION carcinogenesis , *RADIOTHERAPY , *RESEARCH funding , *RISK assessment , *TIME , *VINCRISTINE , *DISEASE incidence , *HUMAN research subjects , *SECONDARY primary cancer , *MECHLORETHAMINE - Abstract
Purpose: To determine whether the risk of secondary breast cancer (SBC) is reduced in women with Hodgkin lymphoma (HL) treated with smaller field radiation therapy (SFRT) versus mantle field radiation therapy (MRT).Methods and Materials: We used the BC Cancer Agency (BCCA) Lymphoid Cancer Database to identify female patients treated for HL between January 1961 and December 2009. Radiation therapy volumes were categorized as MRT or SFRT, which included involved field, involved site, or involved nodal radiation therapy. SBC risk estimates were compared using competing risk analysis and Fine and Gray multivariable model: MRT ± chemotherapy, SFRT ± chemotherapy, or chemotherapy-only.Results: Of 734 eligible patients, 75% of the living patients have been followed up for more than 10 years, SBC has developed in 54, and 15 have died of breast cancer. The 20-year estimated risks (competing risk cumulative incidence) for SBC differed significantly: MRT 7.5% (95% confidence interval [CI] 4.4%-11.5%), SFRT 3.1% (95% CI 1.0%-7.7%), and chemotherapy-only 2.2% (95% CI 1.0%-4.8%) (P=.01). Using a Fine and Gray model to control for death and patients lost to follow-up, MRT was associated with a higher risk of SBC (hazard ratio [HR] = 2.9; 95% CI 1.4%-6.0%; P=.004) compared with chemotherapy-only and with SFRT (HR = 3.3; 95% CI 1.3%-8.4%; P=.01). SFRT was not associated with a greater risk of SBC compared with chemotherapy-only (HR = 0.87; 95% CI 0.28%-2.66%; P=.80).Conclusion: This study confirms that large-volume MRT is associated with a markedly increased risk of SBC; however, more modern small-volume RT is not associated with a greater risk of SBC than chemotherapy alone. [ABSTRACT FROM AUTHOR]- Published
- 2017
- Full Text
- View/download PDF
44. Residual Viremia in Treated HIV+ Individuals.
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Conway, Jessica M. and Perelson, Alan S.
- Subjects
- *
THERAPEUTICS , *HIV infections , *VIREMIA , *ANTIRETROVIRAL agents , *VIRAL replication , *DRUG resistance in microorganisms - Abstract
Antiretroviral therapy (ART) effectively controls HIV infection, suppressing HIV viral loads. However, some residual virus remains, below the level of detection, in HIV-infected patients on ART. The source of this viremia is an area of debate: does it derive primarily from activation of infected cells in the latent reservoir, or from ongoing viral replication? Observations seem to be contradictory: there is evidence of short term evolution, implying that there must be ongoing viral replication, and viral strains should thus evolve. However, phylogenetic analyses, and rare emergent drug resistance, suggest no long-term viral evolution, implying that virus derived from activated latent cells must dominate. We use simple deterministic and stochastic models to gain insight into residual viremia dynamics in HIV-infected patients. Our modeling relies on two underlying assumptions for patients on suppressive ART: that latent cell activation drives viral dynamics and that the reproductive ratio of treated infection is less than 1. Nonetheless, the contribution of viral replication to residual viremia in patients on ART may be non-negligible. However, even if the portion of viremia attributable to viral replication is significant, our model predicts (1) that latent reservoir re-seeding remains negligible, and (2) some short-term viral evolution is permitted, but long-term evolution can still be limited: stochastic analysis of our model shows that de novo emergence of drug resistance is rare. Thus, our simple models reconcile the seemingly contradictory observations on residual viremia and, with relatively few parameters, recapitulates HIV viral dynamics observed in patients on suppressive therapy. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
45. Recombination Enhances HIV-1 Envelope Diversity by Facilitating the Survival of Latent Genomic Fragments in the Plasma Virus Population.
- Author
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Immonen, Taina T., Conway, Jessica M., Romero-Severson, Ethan O., Perelson, Alan S., and Leitner, Thomas
- Subjects
- *
HIV , *VIRAL envelopes , *RECOMBINANT proteins , *GENOMICS , *IMMUNE response , *GENETIC mutation , *VIRUS populations - Abstract
HIV-1 is subject to immune pressure exerted by the host, giving variants that escape the immune response an advantage. Virus released from activated latent cells competes against variants that have continually evolved and adapted to host immune pressure. Nevertheless, there is increasing evidence that virus displaying a signal of latency survives in patient plasma despite having reduced fitness due to long-term immune memory. We investigated the survival of virus with latent envelope genomic fragments by simulating within-host HIV-1 sequence evolution and the cycling of viral lineages in and out of the latent reservoir. Our model incorporates a detailed mutation process including nucleotide substitution, recombination, latent reservoir dynamics, diversifying selection pressure driven by the immune response, and purifying selection pressure asserted by deleterious mutations. We evaluated the ability of our model to capture sequence evolution in vivo by comparing our simulated sequences to HIV-1 envelope sequence data from 16 HIV-infected untreated patients. Empirical sequence divergence and diversity measures were qualitatively and quantitatively similar to those of our simulated HIV-1 populations, suggesting that our model invokes realistic trends of HIV-1 genetic evolution. Moreover, reconstructed phylogenies of simulated and patient HIV-1 populations showed similar topological structures. Our simulation results suggest that recombination is a key mechanism facilitating the persistence of virus with latent envelope genomic fragments in the productively infected cell population. Recombination increased the survival probability of latent virus forms approximately 13-fold. Prevalence of virus with latent fragments in productively infected cells was observed in only 2% of simulations when we ignored recombination, while the proportion increased to 27% of simulations when we allowed recombination. We also found that the selection pressures exerted by different fitness landscapes influenced the shape of phylogenies, diversity trends, and survival of virus with latent genomic fragments. Our model predicts that the persistence of latent genomic fragments from multiple different ancestral origins increases sequence diversity in plasma for reasonable fitness landscapes. [ABSTRACT FROM AUTHOR]
- Published
- 2015
- Full Text
- View/download PDF
46. A familial risk enriched cohort as a platform for testing early interventions to prevent severe mental illness.
- Author
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Uher, Rudolf, Cumby, Jill, MacKenzie, Lynn E, Morash-Conway, Jessica, Glover, Jacqueline M, Aylott, Alice, Propper, Lukas, Abidi, Sabina, Bagnell, Alexa, Pavlova, Barbara, Hajek, Tomas, Lovas, David, Pajer, Kathleen, Gardner, William, Levy, Adrian, and Alda, Martin
- Abstract
Background: Severe mental illness (SMI), including schizophrenia, bipolar disorder and severe depression, is responsible for a substantial proportion of disability in the population. This article describes the aims and design of a research study that takes a novel approach to targeted prevention of SMI. It is based on the rationale that early developmental antecedents to SMI are likely to be more malleable than fully developed mood or psychotic disorders and that low-risk interventions targeting antecedents may reduce the risk of SMI. Methods/Design: Families Overcoming Risks and Building Opportunities for Well-being (FORBOW) is an accelerated cohort study that includes a large proportion of offspring of parents with SMI and embeds intervention trials in a cohort multiple randomized controlled trial (cmRCT) design. Antecedents are conditions of the individual that are distressing but not severely impairing, predict SMI with moderate-to-large effect sizes and precede the onset of SMI by at least several years. FORBOW focuses on the following antecedents: affective lability, anxiety, psychotic-like experiences, basic symptoms, sleep problems, somatic symptoms, cannabis use and cognitive delay. Enrolment of offspring over a broad age range (0 to 21 years) will allow researchers to draw conclusions on a longer developmental period from a study of shorter duration. Annual assessments cover a full range of psychopathology, cognitive abilities, eligibility criteria for interventions and outcomes. Pre-emptive early interventions (PEI) will include skill training for parents of younger children and courses in emotional well-being skills based on cognitive behavioural therapy for older children and youth. A sample enriched for familial risk of SMI will enhance statistical power for testing the efficacy of PEI. Discussion: FORBOW offers a platform for efficient and unbiased testing of interventions selected according to best available evidence. Since few differences exist between familial and ’sporadic’ SMI, the same interventions are likely to be effective in the general population. Comparison of short-term efficacy of PEI on antecedents and the long term efficacy for preventing the onset of SMI will provide an experimental test of the etiological role of antecedents in the development of SMI. [ABSTRACT FROM AUTHOR]
- Published
- 2014
- Full Text
- View/download PDF
47. A Hepatitis C Virus Infection Model with Time-Varying Drug Effectiveness: Solution and Analysis.
- Author
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Conway, Jessica M. and Perelson, Alan S.
- Subjects
- *
HEPATITIS C treatment , *EPIDEMIOLOGICAL models , *DRUG efficacy , *TIME-varying systems , *COMPUTATIONAL biology - Abstract
Simple models of therapy for viral diseases such as hepatitis C virus (HCV) or human immunodeficiency virus assume that, once therapy is started, the drug has a constant effectiveness. More realistic models have assumed either that the drug effectiveness depends on the drug concentration or that the effectiveness varies over time. Here a previously introduced varying-effectiveness (VE) model is studied mathematically in the context of HCV infection. We show that while the model is linear, it has no closed-form solution due to the time-varying nature of the effectiveness. We then show that the model can be transformed into a Bessel equation and derive an analytic solution in terms of modified Bessel functions, which are defined as infinite series, with time-varying arguments. Fitting the solution to data from HCV infected patients under therapy has yielded values for the parameters in the model. We show that for biologically realistic parameters, the predicted viral decay on therapy is generally biphasic and resembles that predicted by constant-effectiveness (CE) models. We introduce a general method for determining the time at which the transition between decay phases occurs based on calculating the point of maximum curvature of the viral decay curve. For the parameter regimes of interest, we also find approximate solutions for the VE model and establish the asymptotic behavior of the system. We show that the rate of second phase decay is determined by the death rate of infected cells multiplied by the maximum effectiveness of therapy, whereas the rate of first phase decline depends on multiple parameters including the rate of increase of drug effectiveness with time. [ABSTRACT FROM AUTHOR]
- Published
- 2014
- Full Text
- View/download PDF
48. Impact of Different Oseltamivir Regimens on Treating Influenza A Virus Infection and Resistance Emergence: Insights from a Modelling Study.
- Author
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Canini, Laetitia, Conway, Jessica M., Perelson, Alan S., and Carrat, Fabrice
- Subjects
- *
OSELTAMIVIR , *INFLUENZA A virus , *DRUG resistance in microorganisms , *PHARMACOKINETICS , *PHARMACODYNAMICS , *VIRAL load , *MATHEMATICAL models , *THERAPEUTICS - Abstract
Several studies have proven oseltamivir to be efficient in reducing influenza viral titer and symptom intensity. However, the usefulness of oseltamivir can be compromised by the emergence and spread of drug-resistant virus. The selective pressure exerted by different oseltamivir therapy regimens have received little attention. Combining models of drug pharmacokinetics, pharmacodynamics, viral kinetics and symptom dynamics, we explored the efficacy of oseltamivir in reducing both symptoms (symptom efficacy) and viral load (virological efficacy). We simulated samples of 1000 subjects using previously estimated between-subject variability in viral and symptom dynamic parameters to describe the observed heterogeneity in a patient population. We simulated random mutations conferring resistance to oseltamivir. We explored the effect of therapy initiation time, dose, intake frequency and therapy duration on influenza infection, illness dynamics, and emergence of viral resistance. Symptom and virological efficacies were strongly associated with therapy initiation time. The proportion of subjects shedding resistant virus was 27-fold higher when prophylaxis was initiated during the incubation period compared with no treatment. It fell to below 1% when treatment was initiated after symptom onset for twice-a-day intakes. Lower doses and prophylaxis regimens led to lower efficacies and increased risk of resistance emergence. We conclude that prophylaxis initiated during the incubation period is the main factor leading to resistance emergence. [ABSTRACT FROM AUTHOR]
- Published
- 2014
- Full Text
- View/download PDF
49. A Stochastic Model of Latently Infected Cell Reactivation and Viral Blip Generation in Treated HIV Patients.
- Author
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Conway, Jessica M. and Coombs, Daniel
- Subjects
- *
STOCHASTIC models , *MATHEMATICAL models , *GENETICS of virus diseases , *HIV infections , *THERAPEUTICS , *LENTIVIRUS diseases , *MEDICAL care of HIV-positive persons - Abstract
Motivated by viral persistence in HIV+ patients on long-term anti-retroviral treatment (ART), we present a stochastic model of HIV viral dynamics in the blood stream. We consider the hypothesis that the residual viremia in patients on ART can be explained principally by the activation of cells latently infected by HIV before the initiation of ART and that viral blips (clinically-observed short periods of detectable viral load) represent large deviations from the mean. We model the system as a continuous-time, multi-type branching process. Deriving equations for the probability generating function we use a novel numerical approach to extract the probability distributions for latent reservoir sizes and viral loads. We find that latent reservoir extinction-time distributions underscore the importance of considering reservoir dynamics beyond simply the half-life. We calculate blip amplitudes and frequencies by computing complete viral load probability distributions, and study the duration of viral blips via direct numerical simulation. We find that our model qualitatively reproduces short small-amplitude blips detected in clinical studies of treated HIV infection. Stochastic models of this type provide insight into treatment-outcome variability that cannot be found from deterministic models. [ABSTRACT FROM AUTHOR]
- Published
- 2011
- Full Text
- View/download PDF
50. Superlattice Patterns in the Complex Ginzburg--Landau Equation with Multiresonant Forcing.
- Author
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Conway, Jessica M. and Riecke, Hermann
- Subjects
- *
SUPERLATTICES , *ENERGY levels (Quantum mechanics) , *EQUATIONS , *FREQUENCIES of oscillating systems , *SPECTRUM analysis , *AMPLITUDE modulation - Abstract
Motivated by the rich variety of complex patterns observed on the surface of fluid layers that are vibrated at multiple frequencies, we investigate the effect of such resonant forcing on systems undergoing a Hopf bifurcation to spatially homogeneous oscillations. We use an extension of the complex Ginzburg-Landau equation that systematically captures weak forcing functions with a spectrum consisting of frequencies close to the 1:1-, the 1:2-, and the 1:3-resonance. By slowly modulating the amplitude of the 1:2-forcing component, we render the bifurcation to subharmonic patterns supercritical despite the quadratic interaction introduced by the 1:3-forcing. Our weakly nonlinear analysis shows that quite generally the forcing function can be tuned such that resonant triad interactions with weakly damped modes stabilize subharmonic superlattice patterns comprising four or five Fourier modes. Using direct simulations of the extended complex Ginzburg-Landau equation, we confirm our weakly nonlinear analysis. In sufficiently large systems domains of different complex patterns compete with each other on a slow time scale. As expected from leading-order energy arguments, with increasing strength of the triad interaction the more complex patterns eventually win out against the simpler patterns. We characterize these ordering dynamics using the spectral entropy of the patterns. For system parameters reported for experiments on the oscillatory Belousov-Zhabotinsky reaction we explicitly show that the forcing parameters can be tuned such that 4-mode patterns are the preferred patterns. [ABSTRACT FROM AUTHOR]
- Published
- 2009
- Full Text
- View/download PDF
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