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1.
J Math Biol ; 88(6): 64, 2024 Apr 17.
Artículo en Inglés | MEDLINE | ID: mdl-38630280

RESUMEN

In this paper, we study in detail the structure of the global attractor for the Lotka-Volterra system with a Volterra-Lyapunov stable structural matrix. We consider the invasion graph as recently introduced in Hofbauer and Schreiber (J Math Biol 85:54, 2022) and prove that its edges represent all the heteroclinic connections between the equilibria of the system. We also study the stability of this structure with respect to the perturbation of the problem parameters. This allows us to introduce a definition of structural stability in ecology in coherence with the classical mathematical concept where there exists a detailed geometrical structure, robust under perturbation, that governs the transient and asymptotic dynamics.


Asunto(s)
Ecología
2.
Int J Immunogenet ; 50(6): 299-305, 2023 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-37735774

RESUMEN

Hepatitis B virus (HBV) is responsible for various liver diseases, such as chronic hepatitis B (CHB), liver fibrosis, liver cirrhosis (LC) and hepatocellular carcinoma (HCC), which pose a significant threat to human health. An ineffective immune response to HBV can result in viral chronicity. Interleukin-37 (IL-37), an immunomodulator, is capable of inhibiting both innate and adaptive immune responses. It is believed that single nucleotide polymorphisms (SNPs) within the IL-37 gene could contribute to the regulation of HBV clearance. Our aim to conduct this study was to investigate whether SNPs in the IL-37 gene were associated with the risk of chronic HBV infection in adults. A total of 342 participants, consisting of 171 cases and 171 controls, were recruited for this study. Sanger sequencing was employed for genotyping six SNPs (rs3811042 G/A, rs3811043 G/C, rs2466449 A/G, rs3811045 C/T, rs3811046 T/G and rs3811047G/A). There was no significant difference in allele and genotype distribution between the two groups, and the constructed haplotypes were not found to be associated with the risk of chronic HBV infection. Our results revealed that there was no relationship between these six SNPs (rs3811042G/A, rs3811043G/C, rs2466449A/G, rs3811045C/T, rs3811046T/G and rs3811047G/A) in the IL-37 gene and susceptibility to chronic HBV infection among Han people in Central China.


Asunto(s)
Carcinoma Hepatocelular , Hepatitis B Crónica , Neoplasias Hepáticas , Adulto , Humanos , Carcinoma Hepatocelular/genética , Estudios de Casos y Controles , China , Predisposición Genética a la Enfermedad , Genotipo , Virus de la Hepatitis B/genética , Hepatitis B Crónica/genética , Cirrosis Hepática/genética , Neoplasias Hepáticas/genética , Polimorfismo de Nucleótido Simple
3.
Chaos Solitons Fractals ; : 113722, 2023 Jun 26.
Artículo en Inglés | MEDLINE | ID: mdl-38620099

RESUMEN

The global impact of COVID-19 has led to the development of numerous mathematical models to understand and control the pandemic. However, these models have not fully captured how the disease's dynamics are influenced by both within-host and between-host factors. To address this, a new mathematical model is proposed that links these dynamics and incorporates immune response. The model is compartmentalized with a fractional derivative in the sense of Caputo-Fabrizio, and its properties are studied to show a unique solution. Parameter estimation is carried out by fitting real-life data, and sensitivity analysis is conducted using various methods. The model is then numerically implemented to demonstrate how the dynamics within infected hosts drive human-to-human transmission, and various intervention strategies are compared based on the percentage of averted deaths. The simulations suggest that a combination of medication to boost the immune system, prevent infected cells from producing the virus, and adherence to COVID-19 protocols is necessary to control the spread of the virus since no single intervention strategy is sufficient.

4.
J Math Biol ; 84(1-2): 2, 2021 12 14.
Artículo en Inglés | MEDLINE | ID: mdl-34905089

RESUMEN

Transcription and translation retrieve and operationalize gene encoded information in cells. These processes are not instantaneous and incur significant delays. In this paper we study Goodwin models of both inducible and repressible operons with state-dependent delays. The paper provides justification and derivation of the model, detailed analysis of the appropriate setting of the corresponding dynamical system, and extensive numerical analysis of its dynamics. Comparison with constant delay models shows significant differences in dynamics that include existence of stable periodic orbits in inducible systems and multistability in repressible systems. A combination of parameter space exploration, numerics, analysis of steady state linearization and bifurcation theory indicates the likely presence of Shilnikov-type homoclinic bifurcations in the repressible operon model.


Asunto(s)
Operón
5.
Euro Surveill ; 26(45)2021 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-34763751

RESUMEN

The SARS-CoV-2 Lambda (Pango lineage designation C.37) variant of interest, initially identified in Peru, has spread to additional countries. First detected in Israel in April 2021 following importations from Argentina and several European countries, the Lambda variant infected 18 individuals belonging to two main transmission chains without further spread. Micro-neutralisation assays following Comirnaty (BNT162b2 mRNA, BioNTech-Pfizer) vaccination demonstrated a significant 1.6-fold reduction in neutralising titres compared with the wild type virus, suggesting increased susceptibility of vaccinated individuals to infection.


Asunto(s)
COVID-19 , SARS-CoV-2 , Vacuna BNT162 , Vacunas contra la COVID-19 , Humanos , Israel/epidemiología , Vacunación
6.
J Math Biol ; 75(5): 1253-1283, 2017 11.
Artículo en Inglés | MEDLINE | ID: mdl-28289838

RESUMEN

This paper analyzes, in the context of a prokaryotic cell, the stochastic variability of the number of proteins when there is a control of gene expression by an autoregulation scheme. The goal of this work is to estimate the efficiency of the regulation to limit the fluctuations of the number of copies of a given protein. The autoregulation considered in this paper relies mainly on a negative feedback: the proteins are repressors of their own gene expression. The efficiency of a production process without feedback control is compared to a production process with an autoregulation of the gene expression assuming that both of them produce the same average number of proteins. The main characteristic used for the comparison is the standard deviation of the number of proteins at equilibrium. With a Markovian representation and a simple model of repression, we prove that, under a scaling regime, the repression mechanism follows a Hill repression scheme with an hyperbolic control. An explicit asymptotic expression of the variance of the number of proteins under this regulation mechanism is obtained. Simulations are used to study other aspects of autoregulation such as the rate of convergence to equilibrium of the production process and the case where the control of the production process of proteins is achieved via the inhibition of mRNAs.


Asunto(s)
Regulación de la Expresión Génica , Modelos Genéticos , Retroalimentación Fisiológica , Homeostasis , Cadenas de Markov , Conceptos Matemáticos , Células Procariotas/metabolismo , Biosíntesis de Proteínas/genética , ARN Mensajero/genética , ARN Mensajero/metabolismo , Procesos Estocásticos
7.
Artículo en Inglés | MEDLINE | ID: mdl-39270419

RESUMEN

OBJECTIVE: This study investigated the protective effect of oxymatrine (OMT) on carbon tetrachloride (CCl4)-induced hepatic fibrosis in mice and explored its possible targets and signaling pathways. METHODS: Male BALB/c mice were randomly divided into blank control, model, positive drug (silymarin), and OMT administration groups, respectively, with 10 mice in each group. Hepatic fibrosis was induced in mice using CCl4 and the corresponding drug intervention was given. After the final administration, ultrasonography tests, blood tests, and analysis of liver differential proteins using tandem mass tag labeling and liquid chromatography-mass spectrometry were performed. RESULTS: OMT intervention ameliorated CCl4-induced hepatic fibrosis in mice, significantly reduced serum alanine aminotransferase and aspartate aminotransferase levels, down-regulated the expression of fibrosis factors, such as type IV collagen IV, laminin, type III procollagen III, and alpha-smooth muscle actin, and improved liver function. The results of the proteomic analysis showed that the intervention of OMT significantly down-regulated 130 out of 440 up-regulated proteins and up-regulated 70 out of 294 down-regulated proteins, primarily involving the transient receptor potential (TRP) signaling pathway, the peroxisome proliferator-activated receptors (PPAR) signaling pathway, and the metabolic pathway of arachidonic acid. The main differential proteins involved were Cyp2c37, SCP-2, and Tbxas1. In addition, OMT intervention significantly reversed the expression of sterol carrier protein-2 (SCP2) and upregulated the expression of peroxisome proliferator-activated receptor gamma, Cyp2c37, and transient receptor potential cation channel subfamily V member 1 proteins. CONCLUSION: OMT inhibited the proliferative capacity of hepatic stellate cells, induced apoptotic properties, and suppressed the development of fibrosis by elevating Cyp2c37/TRP signaling axis activity and upregulating PPAR pathway activity by inhibiting SCP2.

8.
Bioorg Med Chem Lett ; 23(22): 6046-51, 2013 Nov 15.
Artículo en Inglés | MEDLINE | ID: mdl-24094817

RESUMEN

The HIV-1 envelope gp120/gp41 glycoprotein complex plays a critical role in virus-host cell membrane fusion and has been a focus for the development of HIV fusion inhibitors. In this Letter, we present the synthesis of dimers of HIV fusion inhibitor peptides C37H6 and CP32M, which target the trimeric gp41 in the pre-hairpin intermediate state to inhibit membrane fusion. Reactive peptide modules were synthesized using native chemical ligation and then assembled into dimers with varying linker lengths using Cu(I)-catalyzed azide-alkyne cycloaddition (CuAAC) 'click' chemistry. Cell-cell fusion inhibition assays demonstrated that dimers with a (PEG)7 linker showed enhanced antiviral potency over the corresponding monomers. Moreover, the bio-orthogonal nature of the CuAAC 'click' reaction provides a practical way to assemble heterodimers of HIV fusion inhibitors. Heterodimers consisting of the T20-sensitive strain inhibitor C37H6 and the T20-resistant strain inhibitor CP32M were produced that may have broader spectrum activities against both T20-sensitive and T20-resistant strains.


Asunto(s)
Proteína gp120 de Envoltorio del VIH/química , Proteína gp120 de Envoltorio del VIH/metabolismo , Inhibidores de Fusión de VIH/síntesis química , Inhibidores de Fusión de VIH/farmacología , Péptidos/síntesis química , Secuencia de Aminoácidos , Química Clic , Inhibidores de Fusión de VIH/química , VIH-1/efectos de los fármacos , VIH-1/fisiología , Humanos , Fusión de Membrana/efectos de los fármacos , Datos de Secuencia Molecular , Péptidos/farmacología , Multimerización de Proteína , Estructura Secundaria de Proteína
9.
Cell Rep ; 38(2): 110218, 2022 01 11.
Artículo en Inglés | MEDLINE | ID: mdl-34968415

RESUMEN

SARS-CoV-2 Lambda, a variant of interest, has spread in some South American countries; however, its virological features and evolutionary traits remain unclear. In this study, we use pseudoviruses and reveal that the spike protein of the Lambda variant is more infectious than that of other variants due to the T76I and L452Q mutations. The RSYLTPGD246-253N mutation, a unique 7-amino acid deletion in the N-terminal domain of the Lambda spike protein, is responsible for evasion from neutralizing antibodies and further augments antibody-mediated enhancement of infection. Although this mutation generates a nascent N-linked glycosylation site, the additional N-linked glycan is dispensable for the virological property conferred by this mutation. Since the Lambda variant has dominantly spread according to the increasing frequency of the isolates harboring the RSYLTPGD246-253N mutation, our data suggest that the RSYLTPGD246-253N mutation is closely associated with the substantial spread of the Lambda variant in South America.


Asunto(s)
COVID-19/inmunología , Inmunidad/inmunología , SARS-CoV-2/inmunología , Adulto , Anciano , Anticuerpos Neutralizantes/inmunología , Anticuerpos Antivirales/inmunología , Línea Celular , Femenino , Glicosilación , Células HEK293 , Humanos , Masculino , Persona de Mediana Edad , Mutación/inmunología , Glicoproteína de la Espiga del Coronavirus/inmunología
10.
Open Forum Infect Dis ; 9(6): ofac134, 2022 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-35615298

RESUMEN

Background: Coronavirus disease 2019 (COVID-19) infection is a major public health problem in the world and reinfections are becoming more frequent. Our main objective was to describe the epidemiological, clinical, and genomic characteristics of the confirmed cases of reinfection by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in the capital of Lima and Callao, Peru. Methods: We searched in the Peruvian laboratory information system from April 2020 up to May 2021, looking for cases having 2 positive molecular tests for SARS-CoV-2 with more than 90 days between them. We performed genomic sequencing to the available pairs of samples and described the clinical characteristics, epidemiological impact, and genomic analysis of the confirmed reinfections. Results: There were 1 694 164 people with a positive diagnostic test for SARS-CoV-2 in Lima/Callao during the study period. Of these, 1695 had 2 positive molecular tests with more than 90 days between them. Two hundred eleven had both samples available for genomic analysis according to our selection criteria, and these were retrieved and submitted to sequencing. Thirty cases were confirmed to be SARS-CoV-2 reinfections with 2 different lineages in the 2 episodes. The variant Lambda (C.37) was the most common during the second infection and accounted for 19 (63.3%) of the 30 cases. Conclusions: We report 30 cases of confirmed SARS-CoV-2 reinfections. The Lambda variant was the most common cause of the second infections, in concordance with its predominant circulation during Peru's second wave. This report describes the largest series of confirmed reinfections by SARS-CoV-2 in Latin America.We describe the epidemiological, clinical, and genomic characteristics of the confirmed cases of reinfection by severe acute respiratory syndrome coronavirus 2 in Lima and Callao, durante la segunda ola en Peru. The Lambda variant (C.37) was the most common cause of the second infections.

11.
Emerg Microbes Infect ; 11(1): 18-29, 2022 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-34818119

RESUMEN

Severe acute respiratory syndrome coronavirus 2 variants have continued to emerge in diverse geographic locations with a temporal distribution. The Lambda variant containing multiple mutations in the spike protein, has thus far appeared mainly in South America. The variant harbours two mutations in the receptor binding domain, L452Q and F490S, which may change its infectivity and antigenicity to neutralizing antibodies. In this study, we constructed 10 pseudoviruses to study the Lambda variant and each individual amino acid mutation's effect on viral function, and used eight cell lines to study variant infectivity. In total, 12 monoclonal antibodies, 14 convalescent sera, and 23 immunized sera induced by mRNA vaccines, inactivated vaccine, and adenovirus type 5 vector vaccine were used to study the antigenicity of the Lambda variant. We found that compared with the D614G reference strain, Lambda demonstrated enhanced infectivity of Calu-3 and LLC-MK2 cells by 3.3-fold and 1.6-fold, respectively. Notably, the sensitivity of the Lambda variant to 5 of 12 neutralizing monoclonal antibodies, 9G11, AM180, R126, X593, and AbG3, was substantially diminished. Furthermore, convalescent- and vaccine-immunized sera showed on average 1.3-2.5-fold lower neutralizing titres against the Lambda variant. Single mutation analysis revealed that this reduction in neutralization was caused by L452Q and F490S mutations. Collectively, the reduced neutralization ability of the Lambda variant suggests that the efficacy of monoclonal antibodies and vaccines may be compromised during the current pandemic.


Asunto(s)
Anticuerpos Monoclonales/inmunología , Anticuerpos Neutralizantes/inmunología , Vacunas contra la COVID-19/inmunología , COVID-19/inmunología , COVID-19/virología , SARS-CoV-2/genética , SARS-CoV-2/inmunología , Anticuerpos Monoclonales/química , Anticuerpos Neutralizantes/química , Sitios de Unión , COVID-19/prevención & control , Vacunas contra la COVID-19/administración & dosificación , Línea Celular , Interacciones Huésped-Patógeno , Humanos , Sueros Inmunes , Modelos Moleculares , Mutación , Pruebas de Neutralización , Unión Proteica , Glicoproteína de la Espiga del Coronavirus/química , Glicoproteína de la Espiga del Coronavirus/genética , Glicoproteína de la Espiga del Coronavirus/inmunología , Relación Estructura-Actividad , Pseudotipado Viral
12.
J Cell Immunol ; 4(2): 65-71, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-35813003

RESUMEN

Nuclear RNA polymerase (Pol) III synthesizes large amounts of tRNAs and other short non-coding (nc)RNAs by a unique process that involves a termination-associated reinitiation-recycling mechanism. In addition to its two largest of 17 subunits, which contribute to active center RNA-DNA binding and catalytic site, a smaller subunit of ~110 aa (yeast C11, human RPC10) monitors this site, can modify its activity, and is essential for reinitiation-recycling. Distinct, but relevant to human immunity is cytoplasmic (cyto-)Pol III that is a direct sensor of AT-rich viral DNA from which it synthesizes 5'-ppp-RNA signaling molecules that activate interferon (IFN) production. Mutations in genes encoding Pol III subunits cause severe anti-viral immunodeficiency although the mechanisms responsible for cyto-Pol III initiation on this AT-rich DNA are unknown. Cyto-Pol III has also been implicated in inducing IFN in response to cytosolic mitochondrial DNA in autoimmune dysfunction. A focus of this commentary is recent biochemical and genetics research that examined the roles of the individual domains of C11 in the Pol III termination-associated reinitiation-recycling process as well as more recent cryo-EM structural and accompanying analyses, that are considered in evolutionary and other biological contexts. The N-terminal domain (NTD) of C11/RPC10 anchors at the periphery of Pol III from which a highly conserved linker extends to the mobile C-terminal RNA cleavage domain that can reach into the active center and rescue arrested complexes. Biochemical data indicate separable activities for the NTD and CTD in the transcription cycle, whereas the NTD-Linker can confer the evolutionary unique Pol III termination-reinitiation-recycling activity. A model produced from single particle cryo-EM conformations indicates that the C11-Linker-CTD swings in and out of the active center coordinated with allosteric movements of the DNA-binding clamp by the largest subunit, coupling termination to reinitiation-recycling. These may be relevant to DNA loading by cyto-Pol III during immune signaling.

13.
Gene Rep ; 25: 101378, 2021 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-34632160

RESUMEN

Many SARS-CoV-2 variants have high infectivity and transmissibility. The viral genome data show that the COVID-19 curves of daily case numbers were shaped by the emergence of the variants, including Alpha 202012/01 GRY (B.1.1.7; the U.K.), Beta GH/501Y.V2 (B.1.351, B.1.351.2, and B.1.351.3; South Africa), Gamma GR/501Y.V3 (P.1, P.1.1, and P.1.2; Japan, Brazil), Eta G/484K.V3 (B.1.525; Nigeria, the U.K.), Delta G/478K.V1 (B.1.617.2, AY.1, AY.2, and AY.3; India), Iota GH/253G.V1 (B.1.526; the U.S.A.), and Kappa G/452R.V3 (B.1.617.1; India). The Lambda (C.37) variant was reported in Peru initially; this has spread to 41 countries in four continents. Seven out of eight mutations in this variant are associated with the viral spike protein, akin to mutations in the other variants. These mutations have implications for effectiveness of the vaccines and neutralizing antibodies in immunized subjects and those previously infected with the virus and are thought to facilitate the viral invasion into host cells and help the virus evade the host immune system. Widespread dissemination of the viral variants may cause severe clinical consequences, lengthy hospitalizations, and unfavorable prognoses. Healthcare systems will be stretched, and health workers will be fatigued. Fast, equitable, and widespread vaccination with strict adherence to hygiene protocols will control the rising curves of the pandemic due to the new variants.

14.
SIAM J Appl Math ; 80(3): 1307-1335, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-35221385

RESUMEN

Cell division is a process that involves many biochemical steps and complex biophysical mechanisms. To simplify the understanding of what triggers cell division, three basic models that subsume more microscopic cellular processes associated with cell division have been proposed. Cells can divide based on the time elapsed since their birth, their size, and/or the volume added since their birth-the timer, sizer, and adder models, respectively. Here, we propose unified adder-sizer models and investigate some of the properties of different adder processes arising in cellular proliferation. Although the adder-sizer model provides a direct way to model cell population structure, we illustrate how it is mathematically related to the well-known model in which cell division depends on age and size. Existence and uniqueness of weak solutions to our 2+1-dimensional PDE model are proved, leading to the convergence of the discretized numerical solutions and allowing us to numerically compute the dynamics of cell population densities. We then generalize our PDE model to incorporate recent experimental findings of a system exhibiting mother-daughter correlations in cellular growth rates. Numerical experiments illustrating possible average cell volume blowup and the dynamical behavior of cell populations with mother-daughter correlated growth rates are carried out. Finally, motivated by new experimental findings, we extend our adder model cases where the controlling variable is the added size between DNA replication initiation points in the cell cycle.

15.
J Chromatogr A ; 1567: 90-98, 2018 Sep 14.
Artículo en Inglés | MEDLINE | ID: mdl-30007794

RESUMEN

Sea surface temperature determinations based on marine sedimentary C37 alkenone distributions have provided a wealth of data for paleoclimatic studies, including those performed at high resolution. The success of this approach results from several characteristics of alkenone compounds, e.g. their geochemical properties (such as unequivocal synthesis by certain widespread haptophyte algae, plus chemical stability/preservation of the original alkenone distributions during sedimentation), and their analytical properties (such as fast clean up procedures using alkaline hydrolysis of sediment extracts, followed by robust instrumental methods allowing large scale sample processing). Here we show that, in sediments under the influence of continental inputs, coelution of these compounds with cholest-5-enyl 3ß-undecenyl ether and 24-methylcholesta-5,22-dienyl 3ß-undecenyl ether deviate the SST measurements despite alkaline hydrolysis. Here, we report a new high performance liquid chromatrography fractionation method which eliminates these interfering compounds and gathers all the alkenones into a single fraction. These fractions can then be analysed by gas chromatography as in the initial approach, providing large amounts of data as required in high resolution studies.


Asunto(s)
Cromatografía Líquida de Alta Presión , Monitoreo del Ambiente/métodos , Sedimentos Geológicos/química , Cetonas/análisis , Temperatura , Atmósfera/química , Fraccionamiento Químico , Cromatografía de Gases , Monitoreo del Ambiente/instrumentación , Haptophyta/química , Cetonas/química
16.
Rev. peru. med. exp. salud publica ; 39(3): 267-273, jul.-sep. 2022. tab
Artículo en Español | LIPECS, LILACS | ID: biblio-1410002

RESUMEN

RESUMEN Objetivos. Evaluar la respuesta de anticuerpos IgG determinada mediante ELISA utilizando antígenos de los linajes Wuhan y Lambda en trabajadores de la salud con y sin antecedente de infección por SARS-CoV-2 previa a la inmunización con la primera y segunda dosis de la vacuna Sinopharm (BBIBP-CorV). Materiales y métodos. Se realizó un estudio analítico en trabajadores de salud mayores de 18 años. Se incluyeron 51 participantes con antecedente y 100 participantes sin antecedente de infección por SARS-CoV-2, quienes recibieron dos dosis de la vacuna Sinopharm. Los anticuerpos IgG se evaluaron 21 días después de la primera dosis, 21 días después de la segunda dosis y 3 meses después de la segunda dosis mediante una prueba de ELISA in house desarrollado utilizando el antígeno completo del linaje Wuhan (B) y del linaje Lambda(C.37) del virus de SARS-CoV-2. Resultados. En ambos grupos se observó un incremento del porcentaje de personas con anticuerpos luego de la segunda dosis, sin embargo, este porcentaje disminuyó luego de 3 meses de la segunda dosis. Se halló una diferencia significativa entre el índice de anticuerpos medido por ELISA con el antígeno del linaje Wuhan versus el ELISA con el linaje Lambda (p<0,001). Conclusiones. Existe un aumento significativo de la presencia de anticuerpos tipo IgG luego de 15 días de la segunda dosis de la vacunación con BBIP-CORV en los participantes sin infección previa y una disminución, luego de 3 meses de la segunda dosis, de la razón de índices de reactividad de anticuerpos IgG en los ELISA desarrollados con el antígeno de la variante como en los ELISA desarrollados con la variante Lambda.


ABSTRACT Objectives . To evaluate the IgG antibody response by ELISA using Wuhan and Lambda antigens in health care workers with and without history of SARS-CoV-2 infection prior to immunization with the first and second doses of Sinopharm vaccine (BBIBP-CorV). Materials and methods . An analytical study was carried out in health care workers over 18 years of age. Fifty-one participants with history and 100 participants without history of SARS-CoV-2 infection, who received two doses of Sinopharm vaccine, were included. IgG antibodies were assessed 21 days after the first dose, 21 days after the second dose and 3 months after the second dose by in-house ELISA using the complete antigen of the Wuhan variant (B.1.1) and lambda variant (C-37) of SARS-CoV-2 virus. Results . Both groups showed a large increase in the percentage of people with antibodies after the second dose, however, this percentage decreased 3 months after the second dose. The difference between the antibody index measured by ELISA with Wuhan variant antigen versus the ELISA with lambda variant was significant (p<0.001). Conclusions . There is a significant increase in the presence of IgG type antibodies after 15 days of the second dose of BBIBP-CorV vaccination in participants without previous infection and a decrease after 3 months of the second dose in the ratio of IgG antibody reactivity indexes in ELISAs with the variant antigen as with ELISAs with the lambda variant.


Asunto(s)
Humanos , Masculino , Femenino , Adulto , Persona de Mediana Edad , Infecciones por Coronavirus , Inmunidad Humoral , Anticuerpos , Personal de Salud , SARS-CoV-2
17.
J Biol Dyn ; 11(sup1): 192-215, 2017 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-27338168

RESUMEN

HIV latency remains a major obstacle to viral elimination. The activation rate of latently infected cells may depend on the age of latent infection. In this paper, we develop a model of HIV infection including age-structured latently infected cells. We mathematically analyse the model and use numerical simulations with different activation functions to show that the model can explain the persistence of low-level viremia and the latent reservoir stability in patients on therapy. Sensitivity tests suggest that the model is robust to the changes of most parameters but is sensitive to the relative magnitude of the net generation rate and the long-term activation rate of latently infected cells. To reduce the sensitivity, we extend the model to include homeostatic proliferation of latently infected cells. The new model is robust in reproducing the long-term dynamics of the virus and latently infected cells observed in patients receiving prolonged combination therapy.


Asunto(s)
Infecciones por VIH/tratamiento farmacológico , VIH-1/fisiología , Modelos Biológicos , Latencia del Virus , Infecciones por VIH/virología , Humanos
18.
J Biol Dyn ; 11(sup1): 40-64, 2017 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-26889761

RESUMEN

Time delays can affect the dynamics of HIV infection predicted by mathematical models. In this paper, we studied two mathematical models each with two time delays. In the first model with HIV latency, one delay is the time between viral entry into a cell and the establishment of HIV latency, and the other delay is the time between cell infection and viral production. We defined the basic reproductive number and showed the local and global stability of the steady states. Numerical simulations were performed to evaluate the influence of time delays on the dynamics. In the second model with HIV immune response, one delay is the time between cell infection and viral production, and the other delay is the time needed for the adaptive immune response to emerge to control viral replication. With two positive delays, we obtained the stability crossing curves for the model, which were shown to be a series of open-ended curves.


Asunto(s)
Infecciones por VIH/virología , VIH-1/fisiología , Modelos Biológicos , Replicación Viral , Número Básico de Reproducción , Humanos , Modelos Teóricos , Factores de Tiempo , Latencia del Virus
19.
J Biol Dyn ; 11(sup2): 455-483, 2017 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-27730851

RESUMEN

HIV can infect cells via virus-to-cell infection or cell-to-cell viral transmission. These two infection modes may occur in a synergistic way and facilitate viral spread within an infected individual. In this paper, we developed an HIV latent infection model including both modes of transmission and time delays between viral entry and integration or viral production. We analysed the model by defining the basic reproductive number, showing the existence, positivity and boundedness of the solution, and proving the local and global stability of the infection-free and infected steady states. Numerical simulations have been performed to illustrate the theoretical results and evaluate the effects of time delays and fractions of infection leading to latency on the virus dynamics. The estimates of the relative contributions to the HIV latent reservoir and the virus population from the two modes of transmission have also been provided.


Asunto(s)
Infecciones por VIH/transmisión , VIH-1/fisiología , Modelos Biológicos , Latencia del Virus , Número Básico de Reproducción , Infecciones por VIH/virología , Humanos
20.
MethodsX ; 4: 346-359, 2017.
Artículo en Inglés | MEDLINE | ID: mdl-29062720

RESUMEN

Synchrophasor measurements from Phasor Measurement Units (PMUs) are the primary sensors used to deploy Wide-Area Monitoring, Protection and Control (WAMPAC) systems. PMUs stream out synchrophasor measurements through the IEEE C37.118.2 protocol using TCP/IP or UDP/IP. The proposed method establishes a direct communication between two PMUs, thus eliminating the requirement of an intermediate phasor data concentrator, data mediator and/or protocol parser and thereby ensuring minimum communication latency without considering communication link delays. This method allows utilizing synchrophasor measurements internally in a PMU to deploy custom protection and control algorithms. These algorithms are deployed using protection logic equations which are supported by all the PMU vendors. Moreover, this method reduces overall equipment cost as the algorithms execute internally in a PMU and therefore does not require any additional controller for their deployment. The proposed method can be utilized for fast prototyping of wide-area measurements based protection and control applications. The proposed method is tested by coupling commercial PMUs as Hardware-in-the-Loop (HIL) with Opal-RT's eMEGAsim Real-Time Simulator (RTS). As illustrative example, anti-islanding protection application is deployed using proposed method and its performance is assessed. The essential points in the method are: •Bypassing intermediate phasor data concentrator or protocol parsers as the synchrophasors are communicated directly between the PMUs (minimizes communication delays).•Wide Area Protection and Control Algorithm is deployed using logic equations in the client PMU, therefore eliminating the requirement for an external hardware controller (cost curtailment)•Effortless means to exploit PMU measurements in an environment familiar to protection engineers.

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