scholarly journals Global Dynamics and Implications of an HBV Model with Proliferating Infected Hepatocytes

2021 ◽  
Vol 11 (17) ◽  
pp. 8176
Author(s):  
Sarah Hews ◽  
Steffen Eikenberry ◽  
John D. Nagy ◽  
Tin Phan ◽  
Yang Kuang
Keyword(s):  
Liver Failure ◽  
Complex Dynamics ◽  
Stability Result ◽  
Hbv Infection ◽  
Hepatocyte Proliferation ◽  
Global Dynamics ◽  
Inhibition Of Proliferation ◽  
Infected Hepatocyte ◽  
Viral Loads ◽  
Ode Models

Chronic hepatitis B (HBV) infection is a major cause of human suffering, and a number of mathematical models have examined the within-host dynamics of the disease. Most previous models assumed that infected hepatocytes do not proliferate; however, the effect of HBV infection on hepatocyte proliferation is controversial, with conflicting data showing both induction and inhibition of proliferation. With a family of ordinary differential equation (ODE) models, we explored the dynamical impact of proliferation among HBV-infected hepatocytes. Here, we show that infected hepatocyte proliferation in this class of models generates a threshold that divides the dynamics into two categories. Sufficiently compromised proliferation in infected cells produces complex dynamics characterized by oscillating viral loads, whereas higher proliferation generates straightforward dynamics that always results in chronic infection, sometimes with liver failure. A global stability result of the liver failure state was included as it is unique to this class of models. Finally, the model analysis motivated a testable biological hypothesis: Healthy hepatocytes are present in chronic HBV infection if and only if the proliferation of infected hepatocytes is severely impaired.

scholarly journals Efficacy of tenofovir in preventing perinatal transmission of HBV infection in pregnant women with high viral loads

2018 ◽  
Vol 8 (1) ◽  
Author(s):  
Yayun Lin ◽  
Yan Liu ◽  
Guifeng Ding ◽  
Lhousseine Touqui ◽  
Weimin Wang ◽  
...  
Keyword(s):  
Pregnant Women ◽  
Perinatal Transmission ◽  
Hbv Infection ◽  
Viral Loads

Prostaglandin E 2 secreted by mesenchymal stem cells protects against acute liver failure via enhancing hepatocyte proliferation

2018 ◽  
Vol 33 (2) ◽  
pp. 2514-2525 ◽  
Author(s):  
Yang Liu ◽  
Haozhen Ren ◽  
Jinglin Wang ◽  
Faji Yang ◽  
Jun Li ◽  
...  
Keyword(s):  
Stem Cells ◽  
Mesenchymal Stem Cells ◽  
Liver Failure ◽  
Acute Liver Failure ◽  
Hepatocyte Proliferation ◽  
Prostaglandin E

Nonlinear stability and numerical simulations for a reaction–diffusion system modelling Allee effect on predators

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Florinda Capone ◽  
Maria Francesca Carfora ◽  
Roberta De Luca ◽  
Isabella Torcicollo
Keyword(s):  
Numerical Simulations ◽  
Nonlinear Stability ◽  
Allee Effect ◽  
Complex Dynamics ◽  
Stability Result ◽  
Reaction Diffusion ◽  
Reaction Diffusion System ◽  
Diffusion System ◽  
System Modelling ◽  
Oscillatory Pattern

Abstract A reaction–diffusion system governing the prey–predator interaction with Allee effect on the predators, already introduced by the authors in a previous work is reconsidered with the aim of showing destabilization mechanisms of the biologically meaning equilibrium and detecting some aspects for the eventual oscillatory pattern formation. Extensive numerical simulations, depicting such complex dynamics, are shown. In order to complete the stability analysis of the coexistence equilibrium, a nonlinear stability result is shown.

Bifurcations and chaos control in a discrete-time biological model

2020 ◽  
Vol 13 (04) ◽  
pp. 2050022 ◽  
Author(s):  
A. Q. Khan ◽  
T. Khalique
Keyword(s):  
Discrete Time ◽  
Chaos Control ◽  
Control Method ◽  
Complex Dynamics ◽  
Small Neighborhood ◽  
Positive Equilibrium ◽  
Global Dynamics ◽  
Flip Bifurcation ◽  
Time Model ◽  
Predator Prey Model

In this paper, bifurcations and chaos control in a discrete-time Lotka–Volterra predator–prey model have been studied in quadrant-[Formula: see text]. It is shown that for all parametric values, model has boundary equilibria: [Formula: see text], and the unique positive equilibrium point: [Formula: see text] if [Formula: see text]. By Linearization method, we explored the local dynamics along with different topological classifications about equilibria. We also explored the boundedness of positive solution, global dynamics, and existence of prime-period and periodic points of the model. It is explored that flip bifurcation occurs about boundary equilibria: [Formula: see text], and also there exists a flip bifurcation when parameters of the discrete-time model vary in a small neighborhood of [Formula: see text]. Further, it is also explored that about [Formula: see text] the model undergoes a N–S bifurcation, and meanwhile a stable close invariant curves appears. From the perspective of biology, these curves imply that between predator and prey populations, there exist periodic or quasi-periodic oscillations. Some simulations are presented to illustrate not only main results but also reveals the complex dynamics such as the orbits of period-2,3,13,15,17 and 23. The Maximum Lyapunov exponents as well as fractal dimension are computed numerically to justify the chaotic behaviors in the model. Finally, feedback control method is applied to stabilize chaos existing in the model.

scholarly journals 288. Hepatitis B Virus Reactivation in Patients with Hematologic Malignancies after Anticancer Therapy Which Included Ibrutinib

2019 ◽  
Vol 6 (Supplement_2) ◽  
pp. S156-S157 ◽  
Author(s):  
Alexandre Malek ◽  
Yago Nieto ◽  
Ariel D Szvalb ◽  
Shaheer Siddiqui ◽  
Mehnaz A Shafi ◽  
...  
Keyword(s):  
Hepatitis B Virus ◽  
Hepatitis B ◽  
Liver Failure ◽  
Lymphocytic Leukemia ◽  
Hbv Infection ◽  
Temporal Association ◽  
Hbv Reactivation ◽  
Guidance Document ◽  
Cell Transplant ◽  
B Virus

Abstract Background Several cases of severe bacterial, fungal, and viral infections have been reported following ibrutinib therapy. Here, we report a case of a patient with non-Hodgkin lymphoma who developed hepatitis B virus (HBV)–associated liver failure after anti-cancer treatment most recently with ibrutinib. We also review reported cases of HBV reactivation (HBVr) after ibrutinib. Methods We searched the Medline and Embase databases and identified 5 patients with HBVr related to ibrutinib for a total of 6 study patients, including our case (figure). HBV-related outcomes were defined according to the 2018 AASLD HBV guidance document. Results All 6 patients were men and most (5 or 83%) had chronic lymphocytic leukemia and past HBV infection (table). Three patients (50%) developed HBV-related hepatitis and 2 of them progressed to liver failure. Four patients (67%) had a remote history (≥24 months) of other potential risk factors besides ibrutinib that could contribute to HBVr, including the use of direct-acting antivirals for hepatitis C co-infection (1 pt), hematopoietic cell transplant (HCT) (1 pt) and rituximab use (4 patients). HBVr occurred at least 6 months after initiation of ibrutinib in most patients (4 or 67%), with a median of 9.7 months (range, 1.5–42). In all 4 patients pretreated with rituximab, that treatment was completed at least 24 months before HBVr. Two of these patients received anti-HBV prophylaxis that was stopped 12 months after the completion of rituximab; the other 2 patients were only monitored without antivirals. The HCT recipient received anti-HBV prophylaxis per guidelines. None of the 6 patients treated with ibrutinib were receiving anti-HBV prophylaxis at the time of HBVr, but 5 patients were started on anti-HBV drugs at the first sign of HBVr. Four received entecavir and 1, tenofovir. All treated patients recovered from HBVr. No pt died of HBVr. Conclusion Life-threatening HBVr can occur following ibrutinib therapy in patients with past or chronic HBV infection. The temporal association between ibrutinib therapy and reactivation indicates that ibrutinib is the likely cause of the HBVr, and clinicians should be aware of the risk of HBVr in these patients. A provisional approach could be HBV monitoring at regular intervals with initiation of antiviral therapy at the earliest sign of HBV reactivation. Disclosures All authors: No reported disclosures.

scholarly journals Complex Dynamics of an Impulsive Chemostat Model

2019 ◽  
Vol 29 (08) ◽  
pp. 1950101 ◽  
Author(s):  
Jin Yang ◽  
Yuanshun Tan ◽  
Robert A. Cheke
Keyword(s):  
Periodic Solution ◽  
Global Stability ◽  
Substrate Concentration ◽  
Complex Dynamics ◽  
Control Strategies ◽  
Phase Portraits ◽  
Global Dynamics ◽  
Chemostat Model ◽  
Existence And Stability ◽  
Theoretical Results

We propose a novel impulsive chemostat model with the substrate concentration as the basis for the implementation of control strategies, and then investigate the model’s global dynamics. The exact domains of the impulsive and phase sets are discussed in the light of phase portraits of the model, and then we define the Poincaré map and study its complex properties. Furthermore, the existence and stability of the microorganism eradication periodic solution are addressed, and the analysis of a transcritical bifurcation reveals that an order-1 periodic solution is generated. We also provide the conditions for the global stability of an order-1 periodic solution and show the existence of order-[Formula: see text] [Formula: see text] periodic solutions. Moreover, the PRCC results and bifurcation analyses not only substantiate our results, but also indicate that the proposed system exists with complex dynamics. Finally, biological implications related to the theoretical results are discussed.

scholarly journals Local and Global Dynamics of a Constraint Profit Maximization for Bischi–Naimzada Competition Duopoly Game

Mathematics ◽  
2020 ◽  
Vol 8 (9) ◽  
pp. 1458 ◽  
Author(s):  
Sameh S Askar ◽  
Abdulrahman Al-Khedhairi
Keyword(s):  
Complex Dynamics ◽  
Market Competition ◽  
Equilibrium Points ◽  
Profit Maximization ◽  
Stable Complex ◽  
Global Dynamics ◽  
Limited Information ◽  
Critical Curves ◽  
Local And Global Dynamics ◽  
Realistic Situation

The Bischi–Naimzada game is a market competition between two firms with the objective of maximizing profits under limited information. In this article, we study a more generalized and realistic situation that takes into account the sales constraints. we generalize the economic model suggested by Bischi–Naimzada by introducing and studying the maximization of profits based on sales constraints. Our motivation in this paper is the studying of profit and sales constraints maximization and their influences on the game’s dynamics. The local stability of the equilibrium points of the proposed model is discussed. It examines how the dynamics of the proposed two-dimensional competition game model focusing on changes in both the speed of the adjustment and the sales constraint parameters. The map describing the game is proven to be noninvertible and yields many multi-stable, complex dynamics and the coexistence chaotic attractors may arise. The global behavior of the map is achieved by studying the critical curves. The numerical simulations demonstrate the coexistence of two attractors and complex structures of the attraction basins. Several examples are discussed in order to confirm all the analytical results obtained.

New insight in the pathobiology of hepatitis B virus infection

Gut ◽  
2012 ◽  
Vol 61 (Suppl 1) ◽  
pp. i6-i17 ◽  
Author(s):  
Maura Dandri ◽  
Stephen Locarnini
Keyword(s):  
Hepatitis B Virus ◽  
Hepatitis B ◽  
Immune Responses ◽  
Current Knowledge ◽  
Hbv Infection ◽  
Infected Hepatocyte ◽  
Hbv Replication ◽  
Chronic Hepatitis B Virus ◽  
B Virus ◽  
Important Host

Chronic hepatitis B virus (HBV) infection remains a major health burden and the main risk factor for the development of hepatocellular carcinoma worldwide. However, HBV is not directly cytopathic and liver injury appears to be mostly caused by repeated attempts of the host's immune responses to control the infection. Recent studies have shown that the unique replication strategy adopted by HBV enables it to survive within the infected hepatocyte while complex virus–host interplays ensure the virus is able to fulfil its replication requirements yet is still able to evade important host antiviral innate immune responses. Clearer understanding of the host and viral mechanisms affecting HBV replication and persistence is necessary to design more effective therapeutic strategies aimed at improving the management of patients with chronic HBV infection to eventually achieve viral eradication. This article focuses on summarising the current knowledge of factors influencing the course of HBV infection, giving emphasis on the use of novel assays and quantitative serological and intrahepatic biomarkers as tools for predicting treatment response and disease progression.

scholarly journals Systematic profiling of protein complex dynamics reveals DNA-PK phosphorylation of IFI16 en route to herpesvirus immunity

2021 ◽  
Vol 7 (25) ◽  
pp. eabg6680
Author(s):  
Joshua L. Justice ◽  
Michelle A. Kennedy ◽  
Josiah E. Hutton ◽  
Dawei Liu ◽  
Bokai Song ◽  
...  
Keyword(s):  
Dna Damage ◽  
Protein Interactions ◽  
De Novo ◽  
Complex Dynamics ◽  
Nuclear Periphery ◽  
Global Dynamics ◽  
Herpes Simplex Virus 1 ◽  
Time Resolved ◽  
Simplex Virus ◽  
Hsv 1

Dynamically shifting protein-protein interactions (PPIs) regulate cellular responses to viruses and the resulting immune signaling. Here, we use thermal proximity coaggregation (TPCA) mass spectrometry to characterize the on-off behavior of PPIs during infection with herpes simplex virus 1 (HSV-1), a virus with an ancient history of coevolution with hosts. Advancing the TPCA analysis to infer associations de novo, we build a time-resolved portrait of thousands of host-host, virus-host, and virus-virus PPIs. We demonstrate that, early in infection, the DNA sensor IFI16 recruits the active DNA damage response kinase, DNA-dependent protein kinase (DNA-PK), to incoming viral DNA at the nuclear periphery. We establish IFI16 T149 as a substrate of DNA-PK upon viral infection or DNA damage. This phosphorylation promotes IFI16-driven cytokine responses. Together, we characterize the global dynamics of PPIs during HSV-1 infection, uncovering the co-regulation of IFI16 and DNA-PK functions as a missing link in immunity to herpesvirus infection.

Qualitative Research Approaches to Educational Inequality in Latin America

2019 ◽  
Author(s):  
Ana Maria F. Almeida ◽  
Sandra Ziegler
Keyword(s):  
Latin America ◽  
Social Action ◽  
Social Inequalities ◽  
Complex Dynamics ◽  
Educational Inequality ◽  
International Comparisons ◽  
Global Dynamics ◽  
University Departments ◽  
Qualitative Approaches ◽  
And Gender

International comparisons demonstrate considerable educational inequality across Latin America. Since the return of democracy in the region in the mid-1980s, these educational disparities have become an important object of studies and public policies, not least because educational inequality reflects, and entrenches, deep social inequalities across the region. Studies of this phenomenon are multifaceted, with distinctions between qualitative and quantitative approaches corresponding to distinct disciplinary fields (sociology, psychology, history versus economics, notably), university departments (colleges of education, sociology departments versus economics departments), and gender (women versus men). Qualitative approaches examine a limited number of cases, usually using interviews and ethnographies, to examine a circumscribed space of social action, often limited to a small set of institutions within a single national framework. Studies carried out in this perspective support the construction of hypotheses that can then be tested with a larger number of cases. They are particularly suited to identifying multiple, mutually influencing causalities, thus enabling a dense description of the complex dynamics that lead to the reproduction of educational inequality in the region. At the same time, these approaches have not tackled comparative analysis nor have they addressed the global dynamics affecting education in the region.

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