The Experts below are selected from a list of 126 Experts worldwide ranked by ideXlab platform
A. Astolfi - One of the best experts on this subject based on the ideXlab platform.
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Control of HIV Infection Dynamics by the Enhancement of the Immune System
IFAC Proceedings Volumes, 2020Co-Authors: H. Chang, A. AstolfiAbstract:Abstract The human immunodeficiency virus infection, that causes acquired immune deficiency syndrome, is a dynamic process that can be modeled via differential equations. In this paper a control method to boost the response of the immune system by means of drug scheduling is introduced. The control purpose is to steer the system to an equilibrium condition, known as Long-Term Nonprogressor, which corresponds to an infected patient that does not develop the symptoms of acquired immune deficiency syndrome. To show the feasibility of the control methodology a human immunodeficiency virus model is studied analytically and computer simulations are presented.
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Brief paper: Enhancement of the immune system in HIV dynamics by output feedback
Automatica, 2009Co-Authors: H. Chang, A. AstolfiAbstract:The human immunodeficiency virus infection, that causes acquired immune deficiency syndrome, is a dynamic process that can be modeled via differential equations. In this paper we introduce an output feedback method designed for antiretroviral drug therapy to control the immune response. The purpose of the method is to steer the system to an equilibrium condition, the Long-Term Nonprogressor, which corresponds to an infected patient who does not develop the symptoms of acquired immune deficiency syndrome. The suggested control idea guarantees that the immune state is enhanced to a certain level, which is enough for a typical patient to be driven into the Long-Term Nonprogressor status.
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Activation of Immune Response in Disease Dynamics via Controlled Drug Scheduling
IEEE Transactions on Automation Science and Engineering, 2009Co-Authors: H. Chang, A. AstolfiAbstract:The human immunodeficiency virus (HIV) infection, that causes acquired immune deficiency syndrome (AIDS), is a dynamic process that can be modeled via differential equations. The primary goal of this paper is to introduce a control philosophy to boost the response of the immune system by means of drug scheduling. The control purpose is to steer the system to an equilibrium condition known as Long-Term Nonprogressor, which corresponds to an infected patient that does not develop the symptoms of AIDS. The feasibility of the control methodology is illustrated via simulations on two HIV dynamic models and on a general disease model.
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HIV treatment: With or without explicit modeling of the immune system
2009 European Control Conference (ECC), 2009Co-Authors: H. Chang, A. Astolfi, H. ShimAbstract:The human immunodeficiency virus (HIV) infection, that causes acquired immune deficiency syndrome (AIDS), is a dynamic process that can be modeled via differential equations. By varying the drug effect in the model, we show how to drive any initial state into an equilibrium called the Long-Term Nonprogressor, where the infected patient does not develop the symptoms of AIDS. In this paper we extend the scheduling method of gradual dose reduction, which has recently been justified for an HIV dynamic model, to a more complicated HIV model. We then investigate minimal recovery level of HIV patients by constant dosage, without any immune system modeling. The proposed result can be used for a number of biological models.
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Control of the transition to Long-Term Nonprogressor in tristable HIV dynamics
2008 30th Annual International Conference of the IEEE Engineering in Medicine and Biology Society, 2008Co-Authors: H. Chang, A. AstolfiAbstract:The human immunodeficiency virus (HIV) infection, that causes acquired immune deficiency syndrome (AIDS), is a dynamic process that can be modeled via differential equations. In this paper we apply a control strategy to boost the immune response for a tristable HIV dynamic model. The purpose of this control method is to steer the system to an equilibrium condition known as Long-Term Nonprogressor, which corresponds to an infected patient that does not develop the symptoms of AIDS. The control strategy is implemented by controlled drug scheduling based on the understanding of the immune boosting mechanism. The feasibility of the methodology is illustrated via simulations.
H. Chang - One of the best experts on this subject based on the ideXlab platform.
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Control of HIV Infection Dynamics by the Enhancement of the Immune System
IFAC Proceedings Volumes, 2020Co-Authors: H. Chang, A. AstolfiAbstract:Abstract The human immunodeficiency virus infection, that causes acquired immune deficiency syndrome, is a dynamic process that can be modeled via differential equations. In this paper a control method to boost the response of the immune system by means of drug scheduling is introduced. The control purpose is to steer the system to an equilibrium condition, known as Long-Term Nonprogressor, which corresponds to an infected patient that does not develop the symptoms of acquired immune deficiency syndrome. To show the feasibility of the control methodology a human immunodeficiency virus model is studied analytically and computer simulations are presented.
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Brief paper: Enhancement of the immune system in HIV dynamics by output feedback
Automatica, 2009Co-Authors: H. Chang, A. AstolfiAbstract:The human immunodeficiency virus infection, that causes acquired immune deficiency syndrome, is a dynamic process that can be modeled via differential equations. In this paper we introduce an output feedback method designed for antiretroviral drug therapy to control the immune response. The purpose of the method is to steer the system to an equilibrium condition, the Long-Term Nonprogressor, which corresponds to an infected patient who does not develop the symptoms of acquired immune deficiency syndrome. The suggested control idea guarantees that the immune state is enhanced to a certain level, which is enough for a typical patient to be driven into the Long-Term Nonprogressor status.
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Activation of Immune Response in Disease Dynamics via Controlled Drug Scheduling
IEEE Transactions on Automation Science and Engineering, 2009Co-Authors: H. Chang, A. AstolfiAbstract:The human immunodeficiency virus (HIV) infection, that causes acquired immune deficiency syndrome (AIDS), is a dynamic process that can be modeled via differential equations. The primary goal of this paper is to introduce a control philosophy to boost the response of the immune system by means of drug scheduling. The control purpose is to steer the system to an equilibrium condition known as Long-Term Nonprogressor, which corresponds to an infected patient that does not develop the symptoms of AIDS. The feasibility of the control methodology is illustrated via simulations on two HIV dynamic models and on a general disease model.
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HIV treatment: With or without explicit modeling of the immune system
2009 European Control Conference (ECC), 2009Co-Authors: H. Chang, A. Astolfi, H. ShimAbstract:The human immunodeficiency virus (HIV) infection, that causes acquired immune deficiency syndrome (AIDS), is a dynamic process that can be modeled via differential equations. By varying the drug effect in the model, we show how to drive any initial state into an equilibrium called the Long-Term Nonprogressor, where the infected patient does not develop the symptoms of AIDS. In this paper we extend the scheduling method of gradual dose reduction, which has recently been justified for an HIV dynamic model, to a more complicated HIV model. We then investigate minimal recovery level of HIV patients by constant dosage, without any immune system modeling. The proposed result can be used for a number of biological models.
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Control of the transition to Long-Term Nonprogressor in tristable HIV dynamics
2008 30th Annual International Conference of the IEEE Engineering in Medicine and Biology Society, 2008Co-Authors: H. Chang, A. AstolfiAbstract:The human immunodeficiency virus (HIV) infection, that causes acquired immune deficiency syndrome (AIDS), is a dynamic process that can be modeled via differential equations. In this paper we apply a control strategy to boost the immune response for a tristable HIV dynamic model. The purpose of this control method is to steer the system to an equilibrium condition known as Long-Term Nonprogressor, which corresponds to an infected patient that does not develop the symptoms of AIDS. The control strategy is implemented by controlled drug scheduling based on the understanding of the immune boosting mechanism. The feasibility of the methodology is illustrated via simulations.
Dominique Costagliola - One of the best experts on this subject based on the ideXlab platform.
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prevalence and comparative characteristics of long term Nonprogressors and hiv controller patients in the french hospital database on hiv
AIDS, 2009Co-Authors: Sophie Grabar, G Pialoux, Hana Selingerleneman, Sophie Abgrall, Laurence Weiss, Dominique CostagliolaAbstract:Objective: To estimate the prevalence and characteristics of Long-Term Nonprogressor (LTNP) and HIV controller patients in a very large French cohort of HIV1-infected patients. Methods: In the French Hospital Database on HIV [FHDH, Agence Nationale de Recherches sur le SIDA et les hepatites virales (ANRS) CO4], we selected patients who had been seen in 2005, who had been infected for more than 8 years, who were treatment-naive, and who remained asymptomatic. Patients with these characteristics then categorized as follows: LTNP (>8 years of HIV infection and CD4 cell nadir ≥500/μl), elite LTNP (≥8 years of HIV infection, CD4 cell nadir ≥600/μl, and a positive CD4 slope), HIV controllers (>10 years of HIV infection with 90% of plasma viral load values ≤500copies/ml), and elite controllers (same as HIV controllers, but with last plasma viral load value 50 copies/ml). Among the elite controllers, 32 (46%) were LTNP, eight (12%) were elite LTNP, and one-quarter had a last CD4 cell count less than 500/μl. Conclusion: LTNP, elite LTNP, HIV controller, and elite controller patients are rare phenotypes. Elite LTNP patients are less frequent than HIV controllers. There is little overlap among the four subgroups of patients.
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Combined Genotypes of CCR5, CCR2, SDF1, and HLA Genes Can Predict the Long-Term Nonprogressor Status in Human Immunodeficiency Virus-1-Infected Individuals
Blood, 1999Co-Authors: Magdalena Magierowska, Brigitte Autran, Ioannis Theodorou, Patrice Debré, Françoise Sanson, Y. Rivière, Dominique Charron, Dominique CostagliolaAbstract:Human immunodeficiency virus (HIV)-1–infected Long-Term Nonprogressors (LT-NP) represent less than 5% of HIV-1–infected patients. In this work, we tried to understand whether combined genotypes of CCR5-▵32, CCR2-64I, SDF1-3′A and HLA alleles can predict the LT-NP status. Among the chemokine receptor genotypes, only the frequency of the CCR5-▵32 allele was significantly higher in LT-NP compared with the group of standard progressors. The predominant HLA alleles in LT-NP were HLA-A3, HLA-B14, HLA-B17, HLA-B27, HLA-DR6, and HLA-DR7. A combination of both HLA and chemokine receptor genotypes integrated in a multivariate logistic regression model showed that if a subject is heterozygous for CCR5-▵32 and homozygous for SDF1 wild type, his odds of being LT-NP are increased by 16-fold, by 47-fold when a HLA-B27 allele is present with HLA-DR6 absent, and by 47-fold also if at least three of the following alleles are present: HLA-A3, HLA-B14, HLA-B17, HLA-DR7. This model allowed a correct classification of 70% of LT-NPs and 81% of progressors, suggesting that the host’s genetic background plays an important role in the evolution of HIV-1. The chemokine receptor and chemokine genes along with the HLA genotype can serve as predictors of HIV-1 outcome for classification of HIV-1–infected subjects as LT-NPs or progressors.
Priscilla Biswas - One of the best experts on this subject based on the ideXlab platform.
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Activating Killer Immunoglobulin Receptors and HLA-C: a successful combination providing HIV-1 control
Scientific Reports, 2017Co-Authors: Mauro S. Malnati, Elisabetta Ugolotti, Maria Cristina Monti, Davide De Battista, Irene Vanni, Domenico Bordo, Francesca Sironi, Patrizia Larghero, Eddi Di Marco, Priscilla BiswasAbstract:Several studies demonstrated a relevant role of polymorphisms located within the HLA-B and -C loci and the Killer Immunoglobulin Receptors (KIRs) 3DL1 and 3DS1 in controlling HIV-1 replication. KIRs are regulatory receptors expressed at the surface of NK and CD8+ T-cells that specifically bind HLA-A and -B alleles belonging to the Bw4 supratype and all the -C alleles expressing the C1 or C2 supratype. We here disclose a novel signature associated with the Elite Controller but not with the Long-Term Nonprogressor status concerning 2DS activating KIRs and HLA-C2 alleles insensitive to miRNA148a regulation. Overall, our findings support a crucial role of NK cells in the control of HIV-1 viremia.
Arrigo Benedetto - One of the best experts on this subject based on the ideXlab platform.
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Grossly Defective nef Gene Sequences in a Human Immunodeficiency Virus Type 1-Seropositive Long-Term Nonprogressor
Journal of Virology, 1998Co-Authors: Roberto Salvi, Anna Rosa Garbuglia, Antonino Di Caro, Simonetta Pulciani, Francesco Montella, Arrigo BenedettoAbstract:We have been investigating a Long-Term Nonprogressor who was found to be human immunodeficiency virus type 1 (HIV-1) seropositive in 1985 and has survived with stable CD4 1 T-cell counts (>1,000 CD4 cells/ml) without any AIDS-related illness. We have previously reported that repeated attempts to measure HIV-1 RNA in the peripheral mononuclear cells obtained from this subject have invariably failed. In the present study, we have analyzed the molecular nature of the HIV-1 quasispecies infecting this patient by PCR amplification of two proviral regions, the 5* long terminal repeat (5*LTR)/gag leader and the nef gene, directly from fresh uncultured peripheral mononuclear cells, followed by length polymorphism analysis (with 1994, 1995, and 1996 samples) and sequencing (with a 1996 sample). Only proviral forms with nef deletions were revealed by length polymorphism analysis in samples from all three time points. Sequence analysis of the nef gene from the 1996 sample confirmed the presence of similar proviral quasispecies characterized by the presence of several deletions located in the nef-alone and the nef/U3 overlapping regions. Length polymorphism analysis of the 5*LTR/gag leader region suggested the existence of two major quasispecies populations, one characterized by the presence of forms carrying deletions in the U3 region and the other showing a completely intact, full-length 5*LTR. Evidence of the role of nef gene defects in Long-Term survival of HIV-1-infected patients has been provided so far in two independent investigations involving patients infected with HIV through blood transfusion. Here we show the existence of a similar condition in a subject who acquired HIV-1 seropositivity through the sexual route. Investigations aimed at elucidating the biological basis of the peculiar condition commonly known as Long-Term nonprogressive human immunodeficiency virus type 1 (HIV-1) infection, a condition that affects only a small percentage of the total HIV-1-infected population (33), have rapidly increased in the past few years. For most of the Long-Term Nonprogressor (LTNP) patients investigated, much of the attention has been devoted to the characterization of the specific antiviral host immune response and the genotypic properties of the infecting viral quasispecies (6, 30). The latter approach, generally based on the analysis of PCR-derived molecular clones of specific proviral regions, has generated interesting data. In one of the first studies of this kind, by Michael et al. (26), naturally occurring genotypes of the 59 long terminal repeat (59LTR)/gag leader region were characterized for four LTNP patients. A wide spectrum of intra- and interpatient sequence variability was observed, with a remarkable number of point mutations and length polymorphisms in cis- and trans-acting regulatory elements present in this region. A wide range of functional transcriptional activities was associated with these mutations in a reporter gene assay. In another study by the same group (27), the molecular characterization of the vif, vpr, vpu, tat1, and rev accessory genes, as well as of the nef gene proviral sequences, was carried out for one LTNP patient. This study revealed that 64% of the proviruses present in the peripheral blood mono
