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1.
Phys Chem Chem Phys ; 26(16): 12681-12697, 2024 Apr 24.
Artigo em Inglês | MEDLINE | ID: mdl-38600841

RESUMO

The intrinsic ferromagnetism of two-dimensional transition metal carbide Co2C is remarkable. However, its practical application in spintronic devices is encumbered by a low Curie temperature (TC). To surmount this constraint, double transition-metal carbide CoMC (M = Ti, V, Cr, Mn, Fe, Ni) monolayers are constructed with the aim of improving the magnetic properties and Curie temperature of Co2C. The magnetic properties of CoMC monolayers are comprehensively investigated by first-principles calculations and the effects of hole doping and biaxial strain on the magnetic properties of CoMC (M = V, Cr, Mn) monolayers are also studied. The ground states of CoTiC, CoMnC and CoNiC monolayers all favor ferromagnetic ordering, whereas the CoVC and CoCrC monolayers favor antiferromagnetic ordering and the CoFeC monolayer is non-magnetic. Excitedly, the CoMnC monolayer displays a high total magnetic moment of 4.024µB and a TC of 1366 K. Moreover, the control of hole doping can effectively improve the TC of CoVC, CoCrC, and CoMnC monolayers to 680, 1317, 3044 K, respectively. Finally, applying the in-plain biaxial strain, the CoVC monolayer can be transformed into a ferromagnetic semiconductor under a tensile strain of 6%. The TC values of CoVC, CoCrC, and CoMnC monolayers are tuned by biaxial strain to 440, 1334 and 2390 K, respectively. Their TC above room temperature demonstrates that these monolayers have potential applications in spintronic devices. These theoretical investigations provide valuable insights into guiding experimental synthesis endeavors.

2.
Eur J Clin Pharmacol ; 80(5): 685-696, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38329479

RESUMO

PURPOSE: To establish the population pharmacokinetics (PPK) model of cyclosporine A(CsA) in pediatric patients with thalassemia undergoing allogeneic hematopoietic stem cell transplantation (HSCT), aiming at providing a reference for clinical dose individualization of CsA. METHODS: Children with thalassemia who underwent allogeneic HSCT were enrolled retrospectively. The PPK structural model and the random variable model of CsA were established on NONMEN. And goodness of fit plots (GOFs), visual predictive check (VPC), and bootstrap and normalized prediction distribution errors (NPDE) were used to evaluate the final model. RESULTS: A one-compartment model with first-order absorption was employed to fit the base model. A total of 74 pediatric patients and 600 observations of whole blood concentration were included. The final model included weight (WT) in clearance (CL), alongside post-operative day (POD), fluconazole (FLUC), voriconazole (VORI), posaconazole (POSA), and red blood cell count (RBC) significantly. All the model evaluations were passed. CONCLUSION: In the PPK model based on the pediatric cohort on CsA with thalassemia undergoing allogeneic HSCT, WT, POD, FLUC, VORI, POSA, and RBC were found to be the significant factors influencing CL of CsA. The reliability and robustness of the final model were excellent. It is expected that the PPK model can assist in individualizing dosing strategy clinically.


Assuntos
Transplante de Células-Tronco Hematopoéticas , Talassemia , Humanos , Criança , Ciclosporina/farmacocinética , Imunossupressores/farmacocinética , Estudos Retrospectivos , Reprodutibilidade dos Testes , Modelos Biológicos , Voriconazol , Fluconazol , Talassemia/cirurgia
3.
Spectrochim Acta A Mol Biomol Spectrosc ; 308: 123784, 2024 Mar 05.
Artigo em Inglês | MEDLINE | ID: mdl-38128325

RESUMO

Cr3+-free near-infrared (NIR) phosphors are currently gaining significant attention in various application fields. A novel Fe3+-activated LiAlO2 NIR phosphor was successfully synthesized by high-temperature solid-state method. Under excitation of 391 nm and 467 nm, the phosphor emits near-infrared light with wavelengths ranging from 600 to 850 nm. The emission bands with peaks at 725 nm correspond to the transition from 4T1(4G) to the ground state energy level 6A1(6S). The optical band gap of LiAlO2 was calculated using Density Function Theory (DFT) and diffuse reflectance spectrum, respectively. The thermal stability of the sample was measured under 391 nm and 467 nm excitation, showing that the emission intensity at 413 K is 55.3 % and 52.4 % of the emission intensity at room temperature.

4.
Phys Chem Chem Phys ; 26(1): 267-277, 2023 Dec 21.
Artigo em Inglês | MEDLINE | ID: mdl-38059372

RESUMO

Two-dimensional ferromagnets with a long-range ferromagnetic ordering at finite temperature present a bright prospect for their potential applications in nanoscale spintronic devices. The tuning of their intrinsic ferromagnetism and Curie temperature is essential for the development of next-generation data storage and spintronic devices. In this work, the electronic structures, ferromagnetism and Curie temperature of two-dimensional MnS2 monolayer are controlled by charge doping and electric field using first principles calculations. The results show that the dynamic and thermal stability of monolayer MnS2 for all of the cases can be still maintained. Moreover, there is no existence of phase transition and all MnS2 monolayers at any charge doping concentrations and electric field intensities favor ferromagnetic coupling. For the manipulation of electron doping, the calculated total magnetic moment Mtot of the MnS2 monolayer exhibits an increase from 3.112 to 3.491µB per unit cell. Further analysis indicates that a transition from half-metal to metal occurs by introducing the charge doping and vertical electric field, and the Mn 3d electronic states are the major determinants of ferromagnetism. Additionally, the charge doping enables the magnetic anisotropy energy to transform from an in-plane easy axis to the magnetization direction out of the plane. The Curie temperature Tc of the MnS2 monolayer can be moderately enhanced above room temperature by hole doping and application of a vertical electric field. Remarkably, Tc reaches its peak at 767 K at a hole doping concentration of -0.8e. This work enriches the microscopic understanding of the tuning mechanism of ferromagnetism and supplies a sound theoretical basis for subsequent experimental studies.

5.
Malar J ; 22(1): 334, 2023 Nov 06.
Artigo em Inglês | MEDLINE | ID: mdl-37932775

RESUMO

BACKGROUND: The Hubei Province in China reported its last indigenous malaria case in September 2012, but imported malaria cases, particularly those related to Plasmodium vivax and Plasmodium falciparum, threaten Hubei's malaria-free status. This study investigated the epidemiological changes in P. vivax and P. falciparum malaria in this province to provide scientific evidence for preventing malaria resurgence. METHODS: The prevalence, demographic characteristics, seasonal features, and geographical distribution of malaria were assessed using surveillance data and were compared across three stages: control stage (2005-2009) and elimination stages I (2010-2014) and II (2015-2019). RESULTS: In 2005-2019, 8483 malaria cases were reported, including 5599 indigenous P. vivax cases, 275 imported P. vivax cases, 866 imported P. falciparum cases, and 1743 other cases. Imported P. falciparum cases accounted for 0.07% of all cases reported in 2005, but increased to 78.81% in 2019. Most imported P. vivax and P. falciparum malaria occurred among males, aged 21-60 years, during elimination stages I and II. The number of regions affected by imported P. falciparum and P. vivax increased markedly in Hubei from the control stage to elimination stage II. Overall, 1125 imported P. vivax and P. falciparum cases were detected from 47 other nations. Eight imported cases were detected from other provinces in China. From the control stage to elimination stage II, the number of cases of malaria imported from African countries increased, and that of cases imported from Southeast Asian countries decreased. CONCLUSIONS: Although Hubei has achieved malaria elimination, it faces challenges in maintaining this status. Hence, imported malaria surveillance need to be strengthened to reduce the risk of malaria re-introduction.


Assuntos
Malária Falciparum , Malária Vivax , Malária , Masculino , Humanos , Plasmodium vivax , Malária Falciparum/epidemiologia , Malária/prevenção & controle , Malária Vivax/epidemiologia , China/epidemiologia
6.
Chemosphere ; 313: 137582, 2023 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-36529175

RESUMO

Microplastics (MPs) have emerged as a global concern, with a recent study being the first to detect them in the bloodstream of healthy people. However, precise information regarding the toxic effects of MPs on the human vascular system is currently lacking. In this study, we used human vascular endothelial EA. hy926 cells to examine the toxic potential of polystyrene MPs (PSMPs) under realistic blood concentrations. Our findings indicated that PSMPs can cause oxidative stress by reducing the expression of antioxidants, thereby leading to apoptotic cytotoxicity in EA. hy926 cells. Furthermore, the protective potential of heat shock proteins can be reduced by PSMPs. PSMP-induced apoptosis might also lower the expression of rho-associated protein kinase-1 and nuclear factor-κB expression, thus dampening LRR- and pyrin domain-containing protein 3 in EA. hy926 cells. Moreover, we observed that PSMPs induce vascular barrier dysfunction via the depletion of zonula occludens-1 protein. However, although protein expression of the nuclear hormone receptor 77 was inhibited, no significant increase in ectin-like oxidized low-density lipoprotein receptor-1 was noted in PSMP-treated EA. hy926 cells. These results demonstrate that exposure to PSMPs may not sufficiently increase the risk of developing atherosclerosis. Overall, our research signifies that exposure to realistic blood concentrations of PSMPs is associated with low atherosclerotic cardiovascular risk in humans.


Assuntos
Microplásticos , Poliestirenos , Humanos , Microplásticos/toxicidade , Microplásticos/metabolismo , Poliestirenos/metabolismo , Plásticos/metabolismo , Células Endoteliais/metabolismo , Estresse Oxidativo
7.
J Clin Pharm Ther ; 47(12): 2245-2254, 2022 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-36345158

RESUMO

WHAT IS KNOWN AND OBJECTIVES: Voriconazole has a complex pharmacokinetic profile and exhibits different pharmacokinetic characteristics in adults and children. Nevertheless, few studies have been conducted on the population pharmacokinetics (PPK) of voriconazole in children with haematological malignancies. This study aims to build a PPK model and propose a suitable voriconazole treatment scheme for children with haematological malignancies. METHODS: We retrospectively collected 146 samples from 67 children aged from 1.08 to 17.92 years. The PPK model was established using nonlinear mixed effects modelling (NONMEM). Dosage simulations were conducted on the basis of the final model's covariates. RESULTS AND DISCUSSION: Data were fully characterized by a one-compartment model with first-order absorption and elimination. The weight (WT), CYP2C19 phenotype, and Albumin (ALB) were notable covariates for clearance (CL). The typical values of CL, the volume of distribution (V), and oral bioavailability (F) were 2.29 L/h, 76 L, and 0.902, respectively. The proposed doses for different CYP2C19 genotypes were presented in this ranking: EM (extensive metabolizer) > IM (intermediate metabolizer) > PM (poor metabolizer). Furthermore, higher dosages for light WT patients were recommended while lower ALB levels required lower doses. The probability of achieving the target (PTA) for the recommended doses ranged from 72.2% to 99%. WHAT IS NEW AND CONCLUSION: We successfully built a voriconazole PPK model for children with hematologic malignancies. Dosing regimens were developed for different patients based on the final model, which could enhance the rational use of voriconazole in children with haematological malignancies.


Assuntos
Antifúngicos , Neoplasias Hematológicas , Criança , Humanos , Voriconazol/uso terapêutico , Citocromo P-450 CYP2C19/genética , Estudos Retrospectivos , Neoplasias Hematológicas/tratamento farmacológico
8.
Front Pharmacol ; 13: 1002628, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36313303

RESUMO

Objective: To investigate the factors influencing the pharmacokinetics of mycophenolate mofetil (MMF) in pediatric patients after liver transplantation, and to establish a population pharmacokinetics model, which can provide a reference for clinical dosage adjustment. Methods: A prospective study in a single center was performed on pediatric patients who were administrated with mycophenolate mofetil dispersible tablets (MMFdt) for at least 4 days after liver transplantation continuously. Blood samples were collected in ethylene diamine tetraacetic acid anticoagulant tubes before dosing and 0.5, 1, 2, 4, 8, and 12 h after the morning intake of MMFdt. The concentrations of mycophenolic acid (MPA) in plasma were assayed with a validated reverse-phase high-performance liquid chromatography method. UGT1A8 518C > G, UGT1A9 -275T > A, UGT1A9 -2152C > T, UGT2B7 211G > T, SLC O 1B1 521T > C polymorphism were determined by Sanger sequencing. Nonlinear mixed effects modeling was used to establish the population pharmacokinetics (PPK) model. The predictability and stability of the model were internally evaluated by the goodness of fit plots, visual prediction check, normalized prediction errors, and bootstraps. Results: A two-compartment model with first-order absorption and first-order elimination was established with 115 MPA concentrations from 20 pediatric patients. The final model were: CL/F (L/h) = 14.8×(WT/7.5)0.75×(DOSE/11.16)0.452×е0.06, Ka (h-1) = 2.02×(WT/7.5)-0.25, Vc/F (L) = 6.01×(WT/7.5), Vp/F (L) = 269 (fixed), Q/F (L/h) = 15.4×(WT/7.5)0.75×е1.39. Where CL/F was the apparent clearance rate, Ka was the absorption rate constant, Vc/F was the apparent distribution volume of the central compartment, Vp/F was the apparent distribution volume of the peripheral compartment, Q/F was the atrioventricular clearance rate, WT was the body weight of the subject, and DOSE was the MMFdt administered dose. The model indicated there was large inter-individual variability in CL/F and Q/F after multiple dosing of MMFdt. Internal evaluation results showed that the final model had good stability and prediction performance. Conclusion: A stable and predictive population pharmacokinetic model of MMFdt in pediatric patients after the early stage of liver transplantation was established. The pediatric patient's weight and the dose of MMFdt can be a reference to adjust the MMFdt dose.

9.
Pharmgenomics Pers Med ; 14: 1221-1237, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34594128

RESUMO

PURPOSE: To analyze factors influencing tacrolimus (TAC) trough concentration (C0) in ß-thalassemia major (ß-TM) pediatric patients after allogeneic hematopoietic stem cell transplantation (Allo-HSCT) and to investigate the effects of genotype polymorphism and drug-drug interactions on TAC trough concentration in children with ß-TM. Furthermore, to analyze the correlation between TAC C0 and efficacy and adverse reactions. PATIENTS AND METHODS: Prospectively collection of demographic information and details of combined treatment of patients with ß-TM receiving HSCT, and genotypes of CYP3A4, CYP3A5, and ABCB1 (rs1045642, rs1128503, rs2032582) were obtained for each patient. Univariate analysis and multiple linear regression analysis were used to investigate influencing factors on TAC C0. The impact of different genotypes and the co-administration of azole antifungal drugs on ß-TM patients receiving TAC were evaluated, together with the correlation between acute graft-versus-host disease (aGVHD), infection, and liver injury of TAC C0. RESULTS: A total of 46 patients with 587 concentration data were included. The multiple linear regression results showed that the patient's sex, weight, postoperative time, hemoglobin, platelet count, serum cystatin C, and combined voriconazole were independent influencing factors of the infusion trough concentration/daily dose, C0/Div. Age, body surface area, postoperative time, co-administration of voriconazole, and CYP3A4*18B are independent influencing factors of C0/Dpo. Group comparisons showed that voriconazole can affect TAC C0 administered intravenously (IV) and orally in ß-TM pediatric patients, while patient genotype can affect TAC C0 during oral administration. TAC C0 does not correlate with aGVHD or liver injury, but infection may be associated with TAC C0. CONCLUSION: The concentration of TAC should be closely monitored when co-administered with voriconazole. It is worth considering that the influence of genotype on the trough concentration of oral TAC and individualized drug administration warrant investigation. Finally, this study indicated that C0 is not suitable as an indicator of the efficacy of TAC.

10.
Breast ; 54: 264-271, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-33212422

RESUMO

BACKGROUND: Early integration of palliative care (PC) for patients with advanced cancer has been recommended to improve quality of care. This study aims to describe prevalence, temporal trend and predictors of PC use in metastatic breast cancer (mBCa) patients receiving critical care therapies (CCT; included invasive mechanic ventilation, percutaneous endoscopic gastrostomy tube, total parenteral nutrition, tracheostomy and dialysis). METHODS: The National Inpatient Sample was queried for mBCa patients receiving CCT between 2005 and 2014. Annual percent changes (APC) were calculated for PC prevalence in the overall cohort and subgroups. Multivariable logistic analysis was used to explore predictors of PC use. RESULTS: Of 5833 mBCa patients receiving CCT, 880 (15.09%) received PC. Rate of PC use increased significantly from 2.53% in 2005 to 25.96% in 2014 (APC: 35.75%; p < 0.0001). Higher increase in PC use was observed in South (from 0.65% to 27.11%; APC: 59.42%; p < 0.0001), medium bedsize hospitals (from 3.75% to 26.05%; APC: 38.16%; p = 0.0006) and urban teaching hospitals (from 4.13% to 29.86%; APC: 37.33%; p = 0.0005). Multivariable analysis revealed that year interval, urban teaching hospitals, and invasive mechanical ventilation were associated with increased PC use, while primary diagnosis of gastrointestinal disorders, fractures, metastatic sites from lymph nodes and tracheostomy were associated with lower PC use. CONCLUSIONS: PC use in mBCa patients receiving CCT increases significantly over the period. However, it still remains low. Efforts to illustrate disparities in PC use are needed to improve quality of care for mBCa patients receiving CCT, especially for those hospitalized in rural and nonteaching hospitals.


Assuntos
Neoplasias da Mama/terapia , Disparidades em Assistência à Saúde/tendências , Pacientes Internados/estatística & dados numéricos , Cuidados Paliativos/tendências , Aceitação pelo Paciente de Cuidados de Saúde/estatística & dados numéricos , Idoso , Cuidados Críticos/estatística & dados numéricos , Bases de Dados Factuais , Feminino , Humanos , Modelos Logísticos , Pessoa de Meia-Idade , Prevalência , Qualidade da Assistência à Saúde/tendências , Estados Unidos/epidemiologia
11.
Malar J ; 19(1): 264, 2020 Jul 22.
Artigo em Inglês | MEDLINE | ID: mdl-32698906

RESUMO

BACKGROUND: There have been an increasing number of imported cases of malaria in Hubei Province in recent years. In particular, the number of cases of Plasmodium ovale spp. and Plasmodium malariae significantly increased, which resulted in increased risks during the malaria elimination phase. The purpose of this study was to acquire a better understanding of the epidemiological characteristics of P. ovale spp. and P. malariae imported to Hubei Province, China, so as to improve case management. METHODS: Data on all malaria cases from January 2014 to December 2018 in Hubei Province were extracted from the China national diseases surveillance information system (CNDSIS). This descriptive study was conducted to analyse the prevalence trends, latency periods, interval from onset of illness to diagnosis, and misdiagnosis of cases of P. ovale spp. and P. malariae malaria. RESULTS: During this period, 634 imported malaria cases were reported, of which 87 P. ovale spp. (61 P. ovale curtisi and 26 P. ovale wallikeri) and 18 P. malariae cases were confirmed. The latency periods of P. ovale spp., P. malariae, Plasmodium vivax, and Plasmodium falciparum differed significantly, whereas those of P. ovale curtisi and P. ovale wallikeri were no significant difference. The proportion of correct diagnosis of P. ovale spp. and P. malariae malaria cases were 48.3% and 44.4%, respectively, in the hospital or lower-level Centers for Disease Control and Prevention (CDC). In the Provincial Reference Laboratory, the sensitivity of microscopy and rapid diagnostic tests was 94.3% and 70.1%, respectively, for detecting P. ovale spp., and 88.9% and 38.9%, respectively, for detecting P. malariae. Overall, 97.7% (85/87) of P. ovale spp. cases and 94.4% (17/18) of P. malariae cases originated from Africa. CONCLUSION: The increase in the number of imported P. ovale spp. and P. malariae cases, long latency periods, and misdiagnosis pose a challenge to this region. Therefore, more attention should be paid to surveillance of imported cases of P. ovale spp. and P. malariae infection to reduce the burden of public health and potential risk of malaria.


Assuntos
Doenças Transmissíveis Importadas/epidemiologia , Erros de Diagnóstico/estatística & dados numéricos , Infecção Latente/diagnóstico , Malária , Plasmodium malariae/isolamento & purificação , Plasmodium ovale/isolamento & purificação , China/epidemiologia , Infecção Latente/epidemiologia , Malária/diagnóstico , Malária/epidemiologia , Malária/transmissão , Prevalência
12.
Am J Trop Med Hyg ; 103(4): 1534-1539, 2020 10.
Artigo em Inglês | MEDLINE | ID: mdl-32700677

RESUMO

This study aimed to describe the epidemiology of Plasmodium falciparum malaria and identify risk factors for severe disease in Hubei Province, China, using a case-based survey of retrospective data from 2013 to 2018. From 2013 to 2018, a total of 763 imported malaria cases were reported in Hubei Province; 69.2% (528/763) cases were caused by P. falciparum species. The proportion of malaria caused by P. falciparum increased from 66.7% in 2013 to 74.0% in 2018 (χ2 = 21.378, P < 0.05). Plasmodium falciparum malaria was reported in 77 counties of Hubei Province. The majority of imported P. falciparum cases originated from Africa (98.9%, 522/528); 9.7% (51/528) of patients infected with P. falciparum developed severe malaria. Three deaths (case fatality rate: 0.6%) were related to imported P. falciparum malaria. Risk factors for severe malaria were being female (odds ratio [OR] = 3.593, 95% CI: 1.003-12.874), age ≥ 50 years (OR = 2.674, 95% CI: 1.269-5.634), > 3 days between symptom onset and diagnosis (OR = 2.383, 95% CI: 1.210-4.693), and the first-visit medical institution at the township level or lower (OR = 2.568, 95% CI: 1.344-4.908). Malaria prevention should be undertaken among high-risk groups, infection with P. falciparum should be detected early to prevent severe disease and death, and healthcare providers in health facilities at the township level should be trained on early recognition of malaria.


Assuntos
Malária Falciparum/epidemiologia , Plasmodium falciparum/fisiologia , Adulto , China/epidemiologia , Feminino , Humanos , Malária Falciparum/parasitologia , Masculino , Pessoa de Meia-Idade , Razão de Chances , Estudos Retrospectivos , Fatores de Risco
13.
ACS Appl Mater Interfaces ; 10(31): 26128-26141, 2018 Aug 08.
Artigo em Inglês | MEDLINE | ID: mdl-30001104

RESUMO

The self-assembling peptide (SAP) RADA 16-I has been modified with various functional motifs to improve its performances in biomedical applications. Nevertheless, the assembly mechanisms of designer functional RADA 16-I SAPs (F-SAPs) have not been clearly illustrated. The main problem is the difficulty in preparing a completely molecular aqueous solution of F-SAP. In the current study, we demonstrated that different procedures for preparing the F-SAP solution could result in the formation of different conformations and consequently micro/macroscopic morphologies. F-SAP was molecularly dissolved in an appropriate solvent, such as hexafluoroisopropanol (HFIP), as evidenced by random coil conformation characterized by circular dichroism spectroscopy and morphologies under transmission electron microscopy. The monomers were induced into monolayers when the F-SAP solution in HFIP was adsorbed on mica as observed by atomic force microscopy. However, nanoscaled filaments containing ß-sheets dominated in the F-SAP aqueous solution, in which case water acted as a poor solvent of F-SAP. Furthermore, the results of molecular dynamics simulation implicated that water facilitated F-SAP aggregation, whereas HFIP inhibited it. The ß-sheet assemblies formed in water exhibited a high kinetic stability and did not disassemble rapidly after the addition of HFIP. Our study indicated that selecting the right assembly pathway of F-SAP required for targeted functions, for example, delivery of hydrophobic drugs in aqueous conditions, could be achieved by optimizing the preparation protocol in addition to molecular design. Moreover, hierarchical scaffolds mimicking the natural extracellular matrix could be fabricated by the direct electrospinning of F-SAP molecular solution in HFIP and biodegradable polymer for applications in neural regeneration by promoting neural differentiation, neurite outgrowth, and synapse formation.


Assuntos
Regeneração Nervosa , Hidrogéis , Microscopia de Força Atômica , Nanofibras , Peptídeos
14.
Biomed Mater ; 13(3): 035011, 2018 03 16.
Artigo em Inglês | MEDLINE | ID: mdl-29546848

RESUMO

RADA16-I (Ac-(RADA)4-CONH2) is a widely investigated self-assembling peptide (SAP) in the biomedical field. It can undergo ordered self-assembly to form stable secondary structures, thereby further forming a nanofiber hydrogel. The modification of RADA16-I with functional peptide motifs has become a popular research topic. Researchers aim to exhibit particular biomedical signaling, and subsequently, further expand its applications. However, only a few fundamental reports are available on the influences of the peptide motifs on self-assembly mechanisms of designer functional RADA16-I SAPs. In this study, we designed RGD-modified RADA16-I SAPs with a series of net charges and amphiphilicities. The assembly/reassembly of these functionally designer SAPs was thoroughly studied using Raman spectroscopy, CD spectroscopy, and AFM. The nanofiber morphology and the secondary structure largely depended on the balance between the hydrophobic effects versus like-charge repulsions of the motifs, which should be to the focus in order to achieve a tailored nanostructure. Our study would contribute insight into considerations for sophisticated design of SAPs for biomedical applications.


Assuntos
Proliferação de Células/efeitos dos fármacos , Hidrogéis/química , Nanofibras/química , Peptídeos/química , Motivos de Aminoácidos , Materiais Biocompatíveis/química , Adesão Celular , Sobrevivência Celular/efeitos dos fármacos , Células Cultivadas , Dicroísmo Circular , Humanos , Interações Hidrofóbicas e Hidrofílicas , Microscopia de Força Atômica , Nanoestruturas/química , Oligopeptídeos/química , Estrutura Secundária de Proteína , Análise Espectral Raman
15.
Acta Biomater ; 72: 266-277, 2018 05.
Artigo em Inglês | MEDLINE | ID: mdl-29578088

RESUMO

In this study, we prepared a multifunctional gene delivery nanovector containing a chitosan (CS) backbone and polyethylenimine (PEI) arms with arginine-glycine-aspartate (RGD)/twin-arginine translocation (TAT) conjugated via polyethylene glycol (PEG). Branched PEI, with a molecular weight of 2000 Da, was used to achieve a balance between biocompatibility and transfection efficiency, whereas RGD/TAT peptides were conjugated for enhanced targeting ability and cellular uptake. Synthesis of the copolymers was confirmed by characterizing the chemical structure with 1H nuclear magnetic resonance and Fourier Transform Infrared Spectroscopy (FTIR). The nanovector was biocompatible with cells and showed excellent capability for DNA condensation; the resulting complexes with DNA were well-formed, and possessed small particle size and reasonable positive charge. Higher gene transfection efficiency, compared to that achieved with PEI (25 kDa), was confirmed in tumor (HeLa cells) and normal cells (293T and NIH 3T3 cells). More importantly, the cells transfected with the chitosan-graft-PEI-PEG/pCMV-EGFP-Ntf3 complex produced sustained neurotrophin-3 with a linear increase in cumulative concentration, which induced neuronal differentiation of neural stem cell and promoted neurite outgrowth. These findings suggested that our multifunctional copolymers might be ideal nanovectors for engineering cells via gene transfection, and could potentially be applied in tumor therapy and regenerative medicine. STATEMENT OF SIGNIFICANCE: We successfully prepared a multifunctional gene delivery nanovector containing branched PEI with a molecular weight of 2000 Da to balance between biocompatibility and transfection efficiency, and RGD/TAT peptides for enhanced targeting ability and cellular uptake. The well-formed CPPP/DNA complexes of small particle size and reasonable positive charges potentially enhanced gene transfection in both tumor and normal cells. More importantly, the CPPP/pCMV-EGFP-Ntf3 complex-transfected 293T cells could produce sustained NT-3 with a constant ratio, which induced neuron differentiation of NSC and promoted neurite outgrowth. Therefore, our study provided an effective strategy for producing neurotrophins by engineering cells with gene delivery, which deserved wide investigation and potential application in regenerative medicine.


Assuntos
Quitosana , Técnicas de Transferência de Genes , Nanopartículas , Regeneração Nervosa , Células-Tronco Neurais/metabolismo , Neurotrofina 3 , Oligopeptídeos , Polietilenoglicóis , Animais , Diferenciação Celular/efeitos dos fármacos , Diferenciação Celular/genética , Quitosana/química , Quitosana/farmacologia , Feminino , Células HeLa , Humanos , Camundongos , Células NIH 3T3 , Nanopartículas/química , Nanopartículas/uso terapêutico , Regeneração Nervosa/efeitos dos fármacos , Regeneração Nervosa/genética , Células-Tronco Neurais/citologia , Neurotrofina 3/biossíntese , Neurotrofina 3/genética , Oligopeptídeos/química , Oligopeptídeos/farmacologia , Polietilenoglicóis/química , Polietilenoglicóis/farmacologia
16.
Malar J ; 17(1): 81, 2018 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-29448927

RESUMO

BACKGROUND: Hubei Province, China, has been operating a malaria elimination programme. This study aimed at investigating the epidemiologic characteristics of malaria in Hubei Province (2005-2016) to plan resource allocation for malaria elimination. METHODS: Data on all malaria cases from 2005 to 2016 in all counties of Hubei Province were extracted from a web-based reporting system. The numbers of indigenous and imported cases during the disease control (2005-2010) and elimination (2011-2016) stages, as well as their spatiotemporal distribution, were compared. RESULTS: A total of 8109 malaria cases were reported from 2005 to 2016 (7270 and 839 cases during the control and elimination stages, respectively). Between 2005 and 2010, indigenous malaria cases comprised the majority of total cases (7114/7270; 97.9%), and Plasmodium vivax malaria cases accounted for most malaria cases (5572/7270; 76.6%). No indigenous malaria cases have been reported in Hubei Province since 2013. Imported malaria cases showed a gradually increasing trend from 2011 to 2016, Plasmodium falciparum was the predominant species in these cases, and the number of counties with imported cases increased from 4 in 2005 to 47 in 2016. During the control and elimination stages, the most likely spatial clusters for indigenous cases included 13 and 11 counties, respectively. However, the cluster of indigenous malaria cases has not been identified since September 2011. For imported cases, the most likely cluster and three secondary clusters during both stages were identified. CONCLUSIONS: Hubei Province has made significant achievements in controlling and eliminating malaria; however, the region now faces some challenges associated with the increasing number and distribution of imported malaria cases. Priorities for malaria elimination should include better management of imported malaria cases, prevention of secondary malaria transmission, and ensuring the sustainability of malaria surveillance.


Assuntos
Controle de Doenças Transmissíveis/métodos , Erradicação de Doenças/métodos , Malária Falciparum/prevenção & controle , Malária Vivax/prevenção & controle , Plasmodium falciparum/isolamento & purificação , Plasmodium vivax/isolamento & purificação , China/epidemiologia , Incidência , Malária Falciparum/epidemiologia , Malária Falciparum/parasitologia , Malária Vivax/epidemiologia , Malária Vivax/parasitologia , Prevalência
17.
Adv Exp Med Biol ; 973: 17-30, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-27379508

RESUMO

Bacterial adherence to the surface of implants functionalized with cell-adhesive biomolecules is a critical first step of infection development. This study was designed to determine how the immobilization of human plasmatic fibronectin (pFN) could impact bacterial and osteoblast cells interaction with the surface during concomitant exposition to the two cell-types. Calibrated suspensions of P. aeruginosa PAOI or S. aureus CIP4.83 bacteria and STRO-1+A osteoblast progenitor cells were mixed, co-seeded on glass coverslips coated or not with pFN and incubated at 37 °C. After 3 h of co-culture, the presence of bacteria did not modify the STRO-1+A cells adherence to glass. pFN coating significantly enhanced STRO-1+A cells, CIP4.83 and PAOI adherence to glass and bacterial interaction with STRO-1+A cells. Confocal laser scanning microscopy observations revealed that cells on the pFN-coated substrate exhibited a greater spreading, better organized network of cytoskeletal filaments, and an increased cellular FN expression than cells on the uncoated substrate. The use of fluorescently labeled pFN showed that adherent STRO-1+A cells were able to remodel and to concentrate coated pFN at the cells surface. Thus, the use of FN coating could increase the risk of bacterial adherence to the material surface, acting either directly onto the coating layer or indirectly on adherent osteoblastic cells. This may increase the infection risk in the presence of bacterial contamination.


Assuntos
Aderência Bacteriana , Fibronectinas/metabolismo , Osteoblastos/citologia , Pseudomonas aeruginosa/fisiologia , Staphylococcus aureus/fisiologia , Células-Tronco/citologia , Antígenos de Superfície , Adesão Celular , Células Cultivadas , Técnicas de Cocultura , Humanos , Osteoblastos/metabolismo , Pseudomonas aeruginosa/crescimento & desenvolvimento , Staphylococcus aureus/crescimento & desenvolvimento , Células-Tronco/metabolismo
18.
Biomed Mater ; 12(1): 015007, 2016 12 09.
Artigo em Inglês | MEDLINE | ID: mdl-27934778

RESUMO

In the current study, we present three designer self-assembling peptides (SAPs) by appending RADA 16-I with epitopes IKVAV, RGD, and YIGSR, which have different net charges and amphiphilic properties at neutral pH. The self-assembly of the designer SAPs is intensively investigated as a function of pH, canion type, and assembly time. The morphologies of the designer SAPs were studied by atomic force microscope. The secondary structure was investigated by circular dichroism. The dynamic viscoelasticity of designer SAP solutions was examined during titration with different alkaline reagents. Our study indicated that both electrostatic and hydrophilic/hydrophobic interactions of the motifs exhibited influences on the self-assembly, consequentially affecting the fiber morphologies and rheological properties. Moreover, NaOH induced a quicker assembly/reassembly of the designer SAPs than Tris because of its strong ionic strength. Therefore, our study gained comprehensive insight into the self-assembling mechanism as references for developing RADA 16-I-based functional SAPs.


Assuntos
Laminina/química , Oligopeptídeos/química , Fragmentos de Peptídeos/química , Peptídeos/química , Motivos de Aminoácidos , Dicroísmo Circular , Epitopos/química , Concentração de Íons de Hidrogênio , Íons , Cinética , Microscopia de Força Atômica , Nanofibras/química , Estrutura Secundária de Proteína , Reologia , Eletricidade Estática , Fatores de Tempo , Substâncias Viscoelásticas
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