Santanu Biswas | Makaut - Academia.edu (original) (raw)

Papers by Santanu Biswas

Circulation, 2018

Introduction: Statin therapy has been shown to reduce future major adverse cardiovascular events ... more Introduction: Statin therapy has been shown to reduce future major adverse cardiovascular events (MACE) in secondary prevention patients and select patients in primary prevention. The coronary arte...

In this article, we propose a general prey-predator model with the presence of Allee effect in pr... more In this article, we propose a general prey-predator model with the presence of Allee effect in prey. We have considered different competition coefficients within the prey population, which leads to the emergent carrying capacity. The stability analysis of the system is discussed. Further, the dynamical behavior of the system is analyzed, taking delay and emergent carrying capacity as bifurcation parameters. Time delay can turn a stable equilibrium into an unstable one. It was shown that our system experiences the Hopf bifurcation, as the delay parameter crosses some critical values. Further increases in delay produce chaos, which can be controlled by the emergent carrying capacity.

International Journal of Bifurcation and Chaos, 2017

In the present article, we make an attempt to investigate the effect of two time delays, logistic... more In the present article, we make an attempt to investigate the effect of two time delays, logistic delay and gestation delay, on an eco-epidemiological model. In the proposed model, strong Allee effect is considered in the growth term of the prey population. We incorporate two time lags and inspect elementary mathematical characteristic of the proposed model such as boundedness, uniform persistence, stability and Hopf-bifurcation for all possible combinations of both delays at the interior equilibrium point of the system. We observe that increase in gestation delay leads to chaotic solutions through the limit cycle. We also observe that the Allee effect play a major role in controlling the chaos. We execute several numerical simulations to illustrate the proposed mathematical model and our analytical findings.

EBioMedicine, 2019

Background: Accurate laboratory diagnosis of HIV is essential to reduce the risk of HIV-positive ... more Background: Accurate laboratory diagnosis of HIV is essential to reduce the risk of HIV-positive individuals transmitting HIV-1 infection. The goal of this study was to identify and assess a panel of host derived plasma miRNAs that could to serve as a prognostic and predictive biomarker to detect early/acute HIV-1 infection. Methods: A total of 372 microRNAs were analyzed in nine plasma samples from HIV-1 infected individuals in the early phase of infection and three healthy controls using the miRNA PCR-array. Seventeen microRNAs were selected and validated in 80 plasma samples from HIV-1 infected individuals in the early phase of infection (20 each of eclipse stage, RNA+ stage, Ag + stage, and Ag + Ab+ stage of HIV-1 patients) and 25 healthy controls. Using the validation study results a plasma miRNA panel was developed and evaluated to detect early/acute HIV-1 infection in 49 blinded samples. Finding: We identified an miRNA panel (P eHIV-1) containing four differentially expressed miRNAs (miR-16-5p, miR-20b-5p, miR-195-5p, and miR-223-3p) that could distinguish early HIV-1 infection from healthy controls with high AUC (1•000[1•00-1•00]), sensitivity (100%), and specificity (100%).We also found that miR-223-3p demonstrates 100% sensitivity and specificity (AUC 1•00[1•00-1•00]) and could distinguish eclipse stage of HIV-1 infection from healthy controls. To detect eclipse stage of HIV-1 infection we also developed a four-miRNA based (miR-16-5p, miR-206, let-7 g-3p, and miR-181c-3p) panel (P E) with AUC 0•999 (0•995-1•000), 100% sensitivity and 95•8% specificity. Interpretation: The miRNA panel, P eHIV-1 is a potential biomarker for detecting early/acute stage of HIV-1infection and could help initiate early antiretroviral treatment, thus preventing the spread of HIV-1 infection.

Nonlinear Dynamics, 2017

In this article, a system of delay differential equations to represent the predator-prey dynamics... more In this article, a system of delay differential equations to represent the predator-prey dynamics with weak Allee effect in the growth of predator population is discussed. The delay parameter regarding the time lag corresponds to the predator gestation period. Mathematical features such as uniform persistence, permanence, stability, Hopf bifurcation at the interior equilibrium point of the system are analyzed and verified by numerical simulations. Bistability between different equilibrium points is properly discussed. The chaotic behaviors of the system are recognized through bifurcation diagram, Poincare section, and maximum Lyapunov exponent. By constructing a suitable Lyapunov functional for the time-delayed model, global asymptotic stability analysis of the positive equilibrium points has been performed separately. It can be observed that the Allee parameter θ can destabilize the non-delay system, whereas θ and the attack rate of predator can stabilize the time-delayed model and can control the chaotic oscillations through period-halving bifurcation. The optimal predator control policy with Allee parameter (θ) as the control parameter is also discussed.

JCI insight, Jan 3, 2018

Cardiac positron emission testing (PET) is more accurate than single photon emission computed tom... more Cardiac positron emission testing (PET) is more accurate than single photon emission computed tomography (SPECT) at identifying coronary artery disease (CAD); however, the 2 modalities have not been thoroughly compared in a real-world setting. We conducted a retrospective analysis of 60-day catheterization outcomes and 1-year major adverse cardiovascular events (MACE) after the transition from a SPECT- to a PET-based myocardial perfusion imaging (MPI) program. MPI patients at Intermountain Medical Center from January 2011-December 2012 (the SPECT era, n = 6,777) and January 2014-December 2015 (the PET era, n = 7,817) were studied. Outcomes studied were 60-day coronary angiography, high-grade obstructive CAD, left main/severe 3-vessel disease, revascularization, and 1-year MACE-revascularization (MACE-revasc; death, myocardial infarction [MI], or revascularization >60 days). Patients were 64 ± 13 years old; 54% were male and 90% were of European descent; and 57% represented a scre...

PloS one, 2018

Significant sex specific differences in the progression of HIV/AIDS have been reported. Several s... more Significant sex specific differences in the progression of HIV/AIDS have been reported. Several studies have implicated steroid hormones in regulating host factor expression and modulating HIV transmission and replication. However, the exact mechanism exerted by steroid hormones estrogen and progesterone in the regulation of HIV-1 replication is still unclear. Results from the current study indicated a dose dependent down regulation of HIV-1 replication in monocyte derived macrophages pre-treated with high concentrations of estrogen or progesterone. To elucidate the molecular mechanisms associated with the down regulation of HIV-1 replication by estrogen and progesterone we used PCR arrays to analyze the expression profile of host genes involved in antiviral responses. Several chemokines, cytokines, transcription factors, interferon stimulated genes and genes involved in type-1 interferon signaling were down regulated in cells infected with HIV-1 pre-treated with high concentrations...

Scientific reports, Jan 7, 2018

Non-coding RNAs and mRNAs have been implicated in replication, pathogenesis and host response in ... more Non-coding RNAs and mRNAs have been implicated in replication, pathogenesis and host response in HIV infection. However, the impact of long intergenic non-coding RNAs (lincRNAs) on HIV-1 and HIV-2 infection is not known. In this study, we have analyzed expression profiles of lincRNAs and mRNAs in monocyte derived macrophages (MDMs) infected with HIV-1/HIV-2 using microarrays. Our study identified many differentially expressed lincRNAs and mRNAs in MDMs infected with HIV-1/HIV-2 compared to uninfected MDMs. Genes involved in glutathione metabolism and lysine degradation were differentially regulated only in HIV-1 infected MDMs. In HIV-2 infected MDMs, CUL 2, SFRS9, and RBBP4 genes were differentially expressed. Furthermore, we found that plasma levels of lincRNA: chr2: 165509129-165519404 and lincRNA: chr12: 57761837-57762303 were better indicators of HIV-1 infection while lincRNA: chr10:128586385-128592960, XLOC_001148 and lincRNA: chr5:87580664-87583451, were better indicators of H...

Sultan Qaboos University Journal for Science [SQUJS], 2016

The role of animal reservoir in the disease dynamics is not yet properly studied. In the present ... more The role of animal reservoir in the disease dynamics is not yet properly studied. In the present investigation a mathematical model of a vector-host-reservoir is proposed and analyzed to observe the global dynamics of the disease. We observe that the disease free equilibrium is globally asymptotically stable if the basic reproduction number ( ) is less than unity whereas unique positive equilibrium is globally asymptotically stable if and transcritical bifurcation occurs at . Our numerical result suggests that the biting rate plays an important role for the propagation of the disease and the recovery rate has not such important contribution towards eradication of the disease. We also perform sensitivity analysis of the model parameters and the results suggest that the death rate of reservoir may be used as a control parameter to eradicate the disease.

Journal of Cardiovascular Magnetic Resonance, 2013

PloS one, 2017

Visceral leishmaniasis (VL) is a deadly neglected tropical disease that poses a serious problem i... more Visceral leishmaniasis (VL) is a deadly neglected tropical disease that poses a serious problem in various countries all over the world. Implementation of various intervention strategies fail in controlling the spread of this disease due to issues of parasite drug resistance and resistance of sandfly vectors to insecticide sprays. Due to this, policy makers need to develop novel strategies or resort to a combination of multiple intervention strategies to control the spread of the disease. To address this issue, we propose an extensive SIR-type model for anthroponotic visceral leishmaniasis transmission with seasonal fluctuations modeled in the form of periodic sandfly biting rate. Fitting the model for real data reported in South Sudan, we estimate the model parameters and compare the model predictions with known VL cases. Using optimal control theory, we study the effects of popular control strategies namely, drug-based treatment of symptomatic and PKDL-infected individuals, insect...

Viruses, May 2, 2016

While human immunodeficiency virus type 1 and 2 (HIV-1 and HIV-2) share many similar traits, majo... more While human immunodeficiency virus type 1 and 2 (HIV-1 and HIV-2) share many similar traits, major differences in pathogenesis and clinical outcomes exist between the two viruses. The differential expression of host factors like microRNAs (miRNAs) in response to HIV-1 and HIV-2 infections are thought to influence the clinical outcomes presented by the two viruses. MicroRNAs are small non-coding RNA molecules which function in transcriptional and post-transcriptional regulation of gene expression. MiRNAs play a critical role in many key biological processes and could serve as putative biomarker(s) for infection. Identification of miRNAs that modulate viral life cycle, disease progression, and cellular responses to infection with HIV-1 and HIV-2 could reveal important insights into viral pathogenesis and provide new tools that could serve as prognostic markers and targets for therapeutic intervention. The aim of this study was to elucidate the differential expression profiles of host ...

Viruses, Jan 12, 2016

Despite significant advancement in vaccine and virus research, influenza continues to be a major ... more Despite significant advancement in vaccine and virus research, influenza continues to be a major public health concern. Each year in the United States of America, influenza viruses are responsible for seasonal epidemics resulting in over 200,000 hospitalizations and 30,000-50,000 deaths. Accurate and early diagnosis of influenza viral infections are critical for rapid initiation of antiviral therapy to reduce influenza related morbidity and mortality both during seasonal epidemics and pandemics. Several different approaches are currently available for diagnosis of influenza infections in humans. These include viral isolation in cell culture, immunofluorescence assays, nucleic acid amplification tests, immunochromatography-based rapid diagnostic tests, etc. Newer diagnostic approaches are being developed to overcome the limitations associated with some of the conventional detection methods. This review discusses diagnostic approaches currently available for detection of influenza vir...

Mathematical Methods in the Applied Sciences, 2016

We propose and analyze a recurrent epidemic model of cholera in the presence of bacteriophage. Th... more We propose and analyze a recurrent epidemic model of cholera in the presence of bacteriophage. The model is extended by general periodic incidence functions for low‐infectious bacterium and high‐infectious bacterium, respectively. A general periodic shedding function for two infected class (phage‐positive and phage‐negative) and a generalized contact and intrinsic growth function for susceptible class are also considered. Under certain biological assumptions, we derive the basic reproduction number (R0) in a periodic environment for the proposed model. We also observe the global stability of the disease‐free equilibrium, existence, permanence, and global stability of the positive endemic periodic solution of our proposed model. Finally, we verify our results with specific functional form. Copyright © 2016 John Wiley & Sons, Ltd.

Viruses, Jan 2, 2016

Influenza virus infection has a significant impact on public health, since it is a major cause of... more Influenza virus infection has a significant impact on public health, since it is a major cause of morbidity and mortality. It is not well-known whether influenza virus infection affects cell death and human immunodeficiency virus (HIV)-1 replication in HIV-1-infected patients. Using a lymphoma cell line, Jurkat, we examined the in vitro effects of pandemic influenza A (H1N1) virus (pH1N1) infection on cell death and HIV-1 RNA production in infected cells. We found that pH1N1 infection increased apoptotic cell death through Fas and Bax-mediated pathways in HIV-1-infected Jurkat cells. Infection with pH1N1 virus could promote HIV-1 RNA production by activating host transcription factors including nuclear factor kappa-light-chain-enhancer of activated B cells (NF-ĸB), nuclear factor of activated T-cells (NFAT) and activator protein 1 (AP-1) through mitogen-activated protein kinases (MAPK) pathways and T-cell antigen receptor (TCR)-related pathways. The replication of HIV-1 latent infec...

International Journal of Bifurcation and Chaos, 2015

In the present paper, we study the effect of gestation delay on a tri-trophic food chain model wi... more In the present paper, we study the effect of gestation delay on a tri-trophic food chain model with Holling type-II functional response. The essential mathematical features of the proposed model are analyzed with the help of equilibrium analysis, stability analysis, and bifurcation theory. Considering time-delay as the bifurcation parameter, the Hopf-bifurcation analysis is carried out around the coexisting equilibrium. The direction of Hopf-bifurcation and the stability of the bifurcating periodic solutions are determined by applying the normal form theory and center manifold theorem. We observe that if the magnitude of the delay is increased, the system loses stability and shows limit cycle oscillations through Hopf-bifurcation. The system also shows the chaotic dynamics via period-doubling bifurcation for further enhancement of time-delay. Our analytical findings are illustrated through numerical simulations.

Mathematical Methods in the Applied Sciences, 2015

The paper explores an eco-epidemiological model of a predator-prey type, where the prey populatio... more The paper explores an eco-epidemiological model of a predator-prey type, where the prey population is subject to infection. The model is basically a combination of S-I type model and a Rosenzweig-MacArthur predator-prey model. The novelty of this contribution is to consider different competition coefficients within the prey population, which leads to the emergent carrying capacity. We explicitly separate the competition between non-infected and infected individuals. This emergent carrying capacity is markedly different to the explicit carrying capacities that have been considered in many ecoepidemiological models. We observed that different intra-class and inter-class competition can facilitate the coexistence of susceptible prey-infected prey-predator, which is impossible for the case of the explicit carrying capacity model. We also show that these findings are closely associated with bi-stability. The present system undergoes bi-stability in two different scenarios: (a) bi-stability between the planner equilibria where susceptible prey co-exists with predator or infected prey and (b) bi-stability between coexistence equilibrium and the planner equilibrium where susceptible prey coexists with infected prey; have been discussed. The conditions for which the system is to be permanent and the global stability of the system around disease-free equilibrium are worked out.

The Korean Journal of Internal Medicine, 2010

Background/Aims: Acute myocardial infarction (AMI) is a leading cause of death. Inflammatory proc... more Background/Aims: Acute myocardial infarction (AMI) is a leading cause of death. Inflammatory processes play an important role in atherosclerosis, which is intimately related to AMI. The aim of this study was to investigate the association between anti-inflammatory and pro-inflammatory cytokines ratios and AMI. Methods: A total of 90 AMI patients and 90 age-and sex-matched controls were recruited in this study. Plasma cytokines and conventional risk factors were determined by standard methods. Results: Patients with AMI showed increased interleukin (IL)-6 and tumor necrosis factor-α levels and lower antito pro-inflammatory cytokine ratios as compared with controls. A multivariate logistic regression analysis revealed that IL-10 to IL-6 ratio was independently associated with the occurrence of AMI (odds ratio [OR], 5.39; 95% confidence interval [CI], 2.39 to 12.17; p < 0.0001). In contrast, IL-6 levels were no longer significant in the multivariate model (OR, 1.02; 95% CI, 0.932 to 1.12; p = 0.603). A receiver operating characteristic (ROC) curve analysis indicated that IL-6 levels and IL-10 to IL-6 ratios were a significant predictor of AMI (area under ROC curve, 0.892 and 0.851, respectively). Conclusions: Our results suggest that the ratio of IL-10 to IL-6 is independently associated with AMI, and reduced levels of this ratio may favor the development of AMI.