Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 38
Filtrar
Más filtros

Banco de datos
Tipo del documento
Intervalo de año de publicación
1.
Small ; 13(20)2017 05.
Artículo en Inglés | MEDLINE | ID: mdl-28383175

RESUMEN

Recent years have witnessed significant progress in molecular probes for cancer diagnosis. However, the conventional molecular probes are designed to be "always-on" by attachment of tumor-targeting ligands, which limits their abilities to diagnose tumors universally due to the variations of targeting efficiency and complex environment in different cancers. Here, it is proposed that a color-convertible, activatable probe is responding to a universal tumor microenvironment for tumor-specific diagnosis without targeting ligands. Based on the significant hallmark of up-regulated hydrogen peroxide (H2 O2 ) in various tumors, a novel unimolecular micelle constructed by boronate coupling of a hydrophobic hyperbranched poly(fluorene-co-2,1,3-benzothiadiazole) core and many hydrophilic poly(ethylene glycol) arms is built as an H2 O2 -activatable fluorescent nanoprobe to delineate tumors from normal tissues through an aggregation-enhanced fluorescence resonance energy transfer strategy. This color-convertible, activatable nanoprobe is obviously blue-fluorescent in various normal cells, but becomes highly green-emissive in various cancer cells. After intravenous injection to tumor-bearing mice, green fluorescent signals are only detected in tumor tissue. These observations are further confirmed by direct in vivo and ex vivo tumor imaging and immunofluorescence analysis. Such a facile and simple methodology without targeting ligands for tumor-specific detection and imaging is worthwhile to further development.


Asunto(s)
Diagnóstico por Imagen/métodos , Colorantes Fluorescentes/química , Micelas , Neoplasias/diagnóstico por imagen , Animales , Benzotiazoles/síntesis química , Benzotiazoles/química , Benzotiazoles/farmacocinética , Color , Colorantes Fluorescentes/síntesis química , Células HeLa , Humanos , Ratones , Especificidad de Órganos , Polietilenglicoles/química , Espectrometría de Fluorescencia , Espectrofotometría Ultravioleta , Distribución Tisular
2.
Soft Matter ; 11(9): 1788-93, 2015 Mar 07.
Artículo en Inglés | MEDLINE | ID: mdl-25608843

RESUMEN

We report on the first systematic study of vesicle conformational change caused by Coulomb interaction between surface charges on a lipid vesicle. The equilibrium configuration of a charged vesicle is found, as the result of the competition between the local bending elastic energy and the long-range electrostatic interaction within the membrane where the counter-ion effects are neglected. Because of the Rayleigh instability, a charged vesicle undergoes conformational transitions as a function of the surface charge density.


Asunto(s)
Liposomas/química , Electricidad Estática
3.
J Chem Phys ; 142(12): 124904, 2015 Mar 28.
Artículo en Inglés | MEDLINE | ID: mdl-25833606

RESUMEN

A classical density functional theory (DFT) is applied to investigate the behavior of compressed polymer brushes composed of hard-sphere chains. The excluded volume interactions among the chain segments are explicitly treated. Two compression systems are used to study the behavior of brush-wall and brush-brush interactions. For the brush-brush systems, an obvious interpenetration zone has been observed. The extent of the interpenetration depends strongly on the grafting density. Furthermore, the repulsive force between the brush and wall or between the two brushes has been obtained as a function of the compression distance. Compared to the prediction of the analytic self-consistent field theory, such force increases more rapidly in the brush-wall compression with high polymer grafting densities or at higher compressions. In the brush-brush compression system, the interpenetration between the two compressed brushes creates a "softer" interaction. The influence of hard-sphere solvents on the behavior of compressed brushes is also discussed.


Asunto(s)
Polímeros/química , Adsorción , Simulación por Computador , Modelos Químicos , Solventes/química
4.
Biomacromolecules ; 15(4): 1355-64, 2014 Apr 14.
Artículo en Inglés | MEDLINE | ID: mdl-24606561

RESUMEN

Chemotherapy is one of the major systemic treatments for cancer, in which the drug release kinetics is a key factor for drug delivery. In the present work, a versatile fluorescence-based real-time monitoring system for intracellular drug release has been developed. First, two kinds of star-conjugated copolymers with different connections (e.g., pH-responsive acylhydrazone and stable ether) between a hyperbranched conjugated polymer (HCP) core and many linear poly(ethylene glycol) (PEG) arms were synthesized. Owing to the amphiphilic three-dimensional architecture, the star-conjugated copolymers could self-assemble into multimicelle aggregates from unimolecular micelles with excellent emission performance in the aqueous medium. When doxorubicin (DOX) as a model drug was encapsulated into copolymer micelles, the emission of star-conjugated copolymer and DOX was quenched. In vitro biological studies revealed that fluorescent intensities of both star-conjugated copolymer and DOX were activated when the drug was released from copolymeric micelles, resulting in the enhanced cellular proliferation inhibition against cancer cells. Importantly, pH-responsive feature of the star-conjugated copolymer with acylhydrazone linkage exhibited accelerated DOX release at a mildly acidic environment, because of the fast breakage of acylhydrazone in endosome or lysosome of tumor cells. Such fluorescent star-conjugated copolymers may open up new perspectives to real-time study of drug release kinetics of polymeric drug delivery systems for cancer therapy.


Asunto(s)
Antibióticos Antineoplásicos/farmacocinética , Portadores de Fármacos/química , Portadores de Fármacos/farmacocinética , Animales , Antibióticos Antineoplásicos/análisis , Doxorrubicina/análisis , Doxorrubicina/farmacocinética , Portadores de Fármacos/administración & dosificación , Portadores de Fármacos/síntesis química , Endocitosis , Fluorescencia , Hidrazonas/química , Concentración de Iones de Hidrógeno , Interacciones Hidrofóbicas e Hidrofílicas , Células MCF-7/efectos de los fármacos , Ratones , Micelas , Estructura Molecular , Células 3T3 NIH/efectos de los fármacos , Polietilenglicoles/química
5.
J Craniofac Surg ; 25(2): 481-4, 2014 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-24531248

RESUMEN

OBJECTIVE: The objective of this study was to introduce the operation essentials for treatment of patients with vein compression so as to obtain a satisfactory decompression without sacrificing veins. METHODS: We chose 15 patients with trigeminal neuralgia caused by venous from June 15, 2010, through June 15, 2011, and performed microvascular decompression for each patient. By collecting clinical data, such as preoperative magnetic resonance imaging scans, key operative procedures, surgical outcomes, and complications, we explored the operation techniques for these patients and finally summarized our experiences and ideas. RESULTS: For all the 15 patients, 9 cases had excellent remission, 3 cases had delayed excellent remission, 1 case had good remission, and 2 cases had failed result; the total remission rate was 86.7%; 3 cases had facial numbness. CONCLUSIONS: For patients with vein compression, we combine the following 4 procedures together: (1) fully releasing the arachnoid around trigeminal nerve, (2) exploration and decompression of the whole trigeminal root from Meckel cave to pons, (3) cauterization of companioned petrosal vein tributaries by bipolar coagulation, and (4) placing Teflon between trigeminal nerve and offending petrosal vein, thus could acquire a satisfactory effect (remission rate, 86.7%).


Asunto(s)
Venas Cerebrales/cirugía , Cirugía para Descompresión Microvascular/métodos , Síndromes de Compresión Nerviosa/cirugía , Nervio Trigémino/cirugía , Neuralgia del Trigémino/cirugía , Adulto , Anciano , Femenino , Humanos , Imagen por Resonancia Magnética , Masculino , Microcirugia , Persona de Mediana Edad , Politetrafluoroetileno/uso terapéutico , Neuralgia del Trigémino/etiología , Venas/cirugía
6.
Chemistry ; 19(33): 10935-44, 2013 Aug 12.
Artículo en Inglés | MEDLINE | ID: mdl-23818407

RESUMEN

Self-assembled poly(N-methylaniline)-lignosulfonate (PNMA-LS) composite spheres with reactive silver-ion adsorbability were prepared from N-methylaniline by using lignosulfonate (LS) as a dispersant. The results show that the PNMA-LS composite consisted of spheres with good size distribution and an average diameter of 1.03-1.27 µm, and the spheres were assembled by their final nanofibers with an average diameter of 19-34 nm. The PNMA-LS composite spheres exhibit excellent silver-ion adsorption; the maximum adsorption capacity of silver ions is up to 2.16 g g(-1) at an adsorption temperature of 308 K. TEM and wide-angle X-ray results of the PNMA-LS composite spheres after absorption of silver ions show that silver ions are reduced to silver nanoparticles with a mean diameter of about 11.2 nm through a redox reaction between the PNMA-LS composite and the silver ions. The main adsorption mechanism between the PNMA-LS composite and the silver ions is chelation and redox adsorption. In particular, a ternary PNMA-LS-Ag composite achieved by using the reducing reaction between PNMA-LS composite spheres and silver ions can be used as an antibacterial material with high bactericidal rate of 99.95 and 99.99% for Escherichia coli and Staphylococcus aureus cells, respectively.


Asunto(s)
Compuestos de Anilina/química , Antibacterianos/química , Lignina/análogos & derivados , Polímeros/química , Plata/química , Adsorción , Antibacterianos/farmacología , Escherichia coli/efectos de los fármacos , Iones/química , Lignina/química , Nanofibras/química , Staphylococcus aureus/efectos de los fármacos
7.
Biomacromolecules ; 14(5): 1678-86, 2013 May 13.
Artículo en Inglés | MEDLINE | ID: mdl-23560391

RESUMEN

A facile strategy for temperature-induced emission enhancement of star conjugated copolymers has been developed for biodetection. The star copolymers (HCP-star-PDMAEMAs) with different poly(2-(dimethylamino)ethyl methacrylate) (PDMAEMA) chain lengths were synthesized from the hyperbranched conjugated polymer (HCP) macroinitiator by atom transfer radical polymerization (ATRP). The star conjugated copolymers exhibited interesting thermoresponsive phase transitions with adjustable lower critical solution temperature (LCST) depending on the pH of copolymer solution. Above the LCST, the emission of HCP-star-PDMAEMAs was enhanced greatly through restriction of intermolecular aggregation of conjugated polymer cores by the collapse of PDMAEMA arms. By changing the PDMAEMA length, the emission performance of HCP-star-PDMAEMAs could be readily adjusted. Correspondingly, this temperature-dependent emission enhancement of HCP-star-PDMAEMAs was successfully applied in the highly sensitive detection of bacteria. Due to the existence of a hyperbranched conjugated core and many thermo-responsive PDMAEMA arms, the detection limit of E. coli could reach 10(2) cfu mL(-1).


Asunto(s)
Borohidruros/química , Escherichia coli/aislamiento & purificación , Metacrilatos/síntesis química , Nylons/síntesis química , Concentración de Iones de Hidrógeno , Espectroscopía de Resonancia Magnética , Conformación Molecular , Polimerizacion , Soluciones , Temperatura , Agua
8.
Int J Pharm ; 643: 123242, 2023 Aug 25.
Artículo en Inglés | MEDLINE | ID: mdl-37467815

RESUMEN

Multifunctional drug delivery platforms represent ideal approaches to reliably targeting pharmacological agents of interest to the complex tumor microenvironment (TME), yet the complicated synthesis processes, high costs, and toxicities associated with these agents have hindered their clinical application to date. In this study, the properties of the TME are leveraged to develop a multifunctional pNAB/AS DNA microgel that is able to actively target tumors. This microgel is generated by a straightforward one-step free radical precipitation polymerization procedure, exhibiting extremely high drug encapsulation efficiency (∼90%), and is responsive to three environmental stimuli including temperature, reduction, and an acidic pH while showing minimal drug leakage under physiological conditions. Through a synergistic combination of appropriate size and aptamer recognition, this microgel is able to reliably facilitate intratumoral drug accumulation and nuclear drug delivery. Critically, pNAB/AS-Dox treatment is associated with specific antitumor activity in vitro and in vivo while retaining a good biosafety profile and causing lower levels of off-target toxicity as compared to free drug treatment. Together, these findings emphasize the potential value of this multifunctional pNAB/AS DNA microgel as a platform amenable to targeted drug delivery to the TME, providing a foundation for further efforts to readily develop multifunctional drug delivery systems.


Asunto(s)
Antineoplásicos , Microgeles , Neoplasias , Humanos , Sistemas de Liberación de Medicamentos/métodos , Antineoplásicos/uso terapéutico , Neoplasias/tratamiento farmacológico , Neoplasias/patología , ADN , Concentración de Iones de Hidrógeno , Doxorrubicina/química , Microambiente Tumoral
9.
Bioconjug Chem ; 23(9): 1915-24, 2012 Sep 19.
Artículo en Inglés | MEDLINE | ID: mdl-22946621

RESUMEN

A novel type of alendronate(ALE)-conjugated amphiphilic hyperbranched copolymer based on a hydrophobic hyperbranched Boltorn H40 (H40) core with ALE targeting moiety and many hydrophilic poly(ethylene glycol) (PEG) arms was synthesized as a carrier for bone-targeted drug delivery. The star copolymer H40-star-PEG/ALE was characterized using nuclear magnetic resonance (NMR), Fourier transformed infrared spectroscopy (FTIR), and gel permeation chromatography (GPC) analysis. Benefiting from its highly branched structure, H40-star-PEG/ALE could form micelles in aqueous solution, which was confirmed by transmission electron microscopy (TEM) and dynamic light scattering (DLS) techniques. The cytotoxicity and hemolysis of the H40-star-PEG/ALE micelles were evaluated via methylthiazoletetrazolium (MTT) assay against NIH/3T3 normal cells and red blood cell (RBC) lysis assay, respectively. As a model anticancer drug, doxorubicin (DOX) was encapsulated into the H40-star-PEG/ALE micelles. The anticancer activity of DOX-loaded micelles was evaluated by MTT assay against an HN-6 human head and neck carcinoma cell line. The strong affinity of H40-star-PEG/ALE micelles to bone was confirmed by the hydroxyapatite (HA) binding assay. These results indicate that the H40-star-PEG/ALE micelles are highly promising bone-targeted drug carriers for skeletal metastases.


Asunto(s)
Alendronato/química , Huesos/efectos de los fármacos , Sistemas de Liberación de Medicamentos , Polietilenglicoles/química , Alendronato/farmacocinética , Animales , Línea Celular Tumoral , Cromatografía en Gel , Citometría de Flujo , Ratones , Células 3T3 NIH , Espectroscopía Infrarroja por Transformada de Fourier
10.
Chemistry ; 18(51): 16571-9, 2012 Dec 14.
Artículo en Inglés | MEDLINE | ID: mdl-23109322

RESUMEN

Electroconductive poly(N-butylaniline)-lignosulfonate (PBA-LS) composite nanospheres were prepared in a facile way by in situ, unstirred polymerization of N-butylaniline with lignosulfonate (LS) as a dispersant and dopant. The LS content was used to optimize the size, structure, electroconductivity, solubility, and silver ion adsorptive capacity of the PBA-LS nanospheres. Uniform PBA-LS10 nanospheres with a minimal mean diameter of 375 nm and high stability were obtained when the LS content was 10 wt %. The PBA-LS10 nanospheres possess an increased electroconductivity of 0.109 S cm(-1) compared with that of poly(N-butylaniline) (0.0751 S cm(-1)). Furthermore, the PBA-LS10 nanospheres have a maximal silver-ion sorption capacity of 815.0 mg g(-1) at an initial silver ion concentration of 50 mmol L(-1) (25 °C for 48 h), an enhancement of 70.4% compared with PBA. Moreover, a sorption mechanism of silver ions on the PBA-LS10 nanospheres is proposed. TEM and wide-angle X-ray diffraction results showed that silver nanoparticles with a diameter size range of 6.8-55 nm was achieved after sorption, indicating that the PBA-LS10 nanospheres had high reductibility for silver ions.


Asunto(s)
Iones/química , Lignina/análogos & derivados , Nanopartículas/química , Nanosferas/química , Plata/química , Adsorción , Lignina/química , Estructura Molecular , Espectrofotometría Infrarroja
11.
Biomacromolecules ; 13(11): 3552-61, 2012 Nov 12.
Artículo en Inglés | MEDLINE | ID: mdl-22998016

RESUMEN

Biodegradable hyperbranched polyglycerols (dHPGs) were synthesized through oxyanionic initiating hybrid polymerization of glycerol and glycidyl methacrylate. Due to the introduction of ester linkages into the hyperbranched polyglycerol backbone, dHPGs showed good biodegradability and low cytotoxicity. Benefiting from the existence of terminal hydroxyls and methacryloyl groups, both the anticancer drug methotrexate (MTX) and fluorescent probe Rhodamine-123 could be conjugated onto the surface of dHPGs easily. The resultant MTX-conjugated polymers (dHPG-MTXs) exhibited an amphiphilic character, resulting in the formation of micelles in an aqueous solution. The release of MTX from micelles was significantly faster at mildly acidic pH of 5.0 compared to physiological pH of 7.4. dHPG-MTX micelles could be efficiently internalized by cancer cells. MTT assay against cancer cells showed dHPG-MTXs micelles had high anticancer efficacy. On the basis of their good biodegradability and low cytotoxicity, dHPGs provide an opportunity to design excellent drug delivery systems.


Asunto(s)
Portadores de Fármacos , Glicerol/química , Metotrexato/administración & dosificación , Metotrexato/química , Polímeros/química , Rodamina 123/administración & dosificación , Rodamina 123/química , Células 3T3 , Animales , Transporte Biológico , Línea Celular Tumoral , Proliferación Celular/efectos de los fármacos , Portadores de Fármacos/química , Glicerol/síntesis química , Glicerol/metabolismo , Células HeLa , Humanos , Metotrexato/farmacología , Ratones , Micelas , Polímeros/síntesis química , Polímeros/metabolismo , Rodamina 123/farmacología
12.
Water Sci Technol ; 66(11): 2275-83, 2012.
Artículo en Inglés | MEDLINE | ID: mdl-23032754

RESUMEN

Polyvinylchloride (PVC) ultrafiltration membranes were modified by blending with single-walled carbon nanotubes (SWCNTs) to improve the membranes' antibacterial property. Both modified and control samples were characterized for pore structure, roughness, hydrophilicity, permeability and mechanical properties. The membranes' antibacterial property was accessed with Escherichia coli as the model microbes by several methods. It was found that, after being blended with SWCNTs, the surface roughness of the modified membrane increased. Also, the surface hydrophilicity was improved. The membrane flux increased accordingly. But the membrane elongation decreased obviously with the SWCNTs addition. The modified membranes did not show the antibacterial property as expected in this research. There was no bacterial inhibition circle around the SWCNTs/PVC membrane coupons in the culture plates. There were no morphological differences of the cells on the control and the modified membranes. Hoechst 33342/propidium iodide stain test showed that there were more than 90% living bacterial cells which could grow on the SWCNTs/PVC membranes. This study suggests that the polymer wrapping may reduce the SWCNTs' antibacterial property greatly.


Asunto(s)
Antibacterianos , Membranas Artificiales , Nanotubos de Carbono , Cloruro de Polivinilo , Bencimidazoles , Recuento de Colonia Microbiana , Escherichia coli/crecimiento & desarrollo
13.
Contrast Media Mol Imaging ; 2022: 8622498, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-35685663

RESUMEN

Background: Median sternotomy is the most applied approach in open-heart surgery, while potential complications such as postoperative bleeding, sternal dehiscence, and deep sternal wound infection (DWSI) still remain a challenge to cardiac surgeons. Several new sternum-closure products instead of stainless wire have been brought into clinical application. The objective of this retrospective study is to evaluate the novel sternum-fixing product in terms of clinical outcomes. Methods: 689 consecutive cases undergoing cardiac surgery through median sternotomy between February 2015 and December 2018 in our center were enrolled in this study. All the cases were divided into two groups according to different sternum fixation methods: wire cerclage group and rigid fixator group. The demographic as well as clinical data including the mediastinal drainage of first, second, and third post-op 24 hours, the total mediastinal drainage of post-op 72 hours, ICU duration, length of hospital stay, and post-op mortality in 30 days were collected and compared between the two groups. Results: 278 cases were enrolled in the wire cerclage group and 411 cases in the rigid fixator group. There is no significant difference in the demographic data between the two groups, while the mediastinal drainage in the first and third 24 hours after surgery and the total mediastinal drainage in postoperative 72 hours of the rigid fixator group were significantly less than those of the wire cerclage group (P < 0.05). No significant difference was found in other clinical outcomes between the groups including ICU duration, LOS in hospital, and 30-day mortality. 14 cases (5.0%) in the wire cerclage group and 11 cases (2.7%) in the rigid fixator group had sternotomy-related complications including severe postoperative bleeding, sternal dehiscence, and DSWI. Conclusion: Compared with the conventional wire cerclage, the new rigid fixator is superior in median sternotomy closure in terms of postoperative mediastinal bleeding as well as incidence of sternotomy-related complications.


Asunto(s)
Esternotomía , Titanio , Aleaciones , Placas Óseas , Humanos , Estudios Retrospectivos , Esternón/cirugía , Dehiscencia de la Herida Operatoria/cirugía , Resultado del Tratamiento
14.
Int J Biol Macromol ; 209(Pt A): 680-691, 2022 Jun 01.
Artículo en Inglés | MEDLINE | ID: mdl-35413323

RESUMEN

Functionalized two-dimensional Ti3C2Tx (TN-EHL) was prepared as an effective adsorbent for removal of methylene blue dye (MB) and copper ions (Cu2+). Enzymatic hydrolysis lignin (EHL), a reproducible natural resource, was used to functionalize the Ti3C2Tx nanosheets. EHL can not only introduce active functional groups into TN-EHL but also prevent the oxidation of Ti3C2Tx, thus promoting the adsorption performance of TN-EHL. The maximum adsorption capacities of TN-EHL50 (in which the EHL content is 50 wt%) for MB and Cu2+ were 293.7 mg g-1 and 49.96 mg g-1, respectively. The higher correlation coefficients (R2) of MB (0.9996) and Cu2+ (0.9995) indicating that their adsorption processes can be described by the pseudo-second-order kinetic model. The MB adsorption data fit the Freundlich isotherm with R2 of 0.9953, whereas the Cu2+ ions adsorption data fit the Langmuir isotherm with R2 of 0.9998. The thermodynamic analysis indicates that the adsorption process of MB and Cu2+ on TN-EHL50 is spontaneous and endothermic. Significantly, the Cu2+ ions were reduced to Cu2O and CuO particles during the adsorption process. Therefore, TN-EHL has a great potential as an environmentally friendly adsorbent for MB removal and recovery of Cu2+ ions from wastewater.


Asunto(s)
Contaminantes Químicos del Agua , Purificación del Agua , Adsorción , Cobre , Hidrólisis , Iones , Cinética , Lignina , Azul de Metileno , Titanio , Contaminantes Químicos del Agua/análisis
15.
Biomacromolecules ; 12(10): 3460-8, 2011 Oct 10.
Artículo en Inglés | MEDLINE | ID: mdl-21863891

RESUMEN

Oxime bonds dispersed in the backbones of the synthetic polymers, while young in the current spectrum of the biomedical application, are rapidly extending into their own niche. In the present work, oxime linkages were confirmed to be a robust tool for the design of pH-sensitive polymeric drug delivery systems. The triblock copolymer (PEG-OPCL-PEG) consisting of hydrophilic poly(ethylene glycol) (PEG) and hydrophobic oxime-tethered polycaprolactone (OPCL) was successfully prepared by aminooxy terminals of OPCL ligating with aldehyde-terminated PEG (PEG-CHO). Owing to its amphiphilic architecture, PEG-OPCL-PEG self-assembled into the micelles in aqueous media, validated by the measurement of critical micelle concentration (CMC). The MTT assay showed that PEG-OPCL-PEG exhibited low cytotoxicity against NIH/3T3 normal cells. Doxorubicin (DOX) as a model drug was encapsulated into the PEG-OPCL-PEG micelles. Drug release study revealed that the DOX release from micelles was significantly accelerated at mildly acid pH of 5.0 compared to physiological pH of 7.4, suggesting the pH-responsive feature of the drug delivery systems with oxime linkages. Flow cytometry and confocal laser scanning microscopy (CLSM) measurements indicated that these DOX-loaded micelles were easily internalized by living cells. MTT assay against HeLa cancer cells showed DOX-loaded PEG-OPCL-PEG micelles had a high anticancer efficacy. All of these results demonstrate that these polymeric micelles self-assembled from oxime-tethered block copolymers are promising carriers for the pH-triggered intracellular delivery of hydrophobic anticancer drugs.


Asunto(s)
Antineoplásicos/farmacología , Doxorrubicina/farmacología , Portadores de Fármacos/síntesis química , Oximas/química , Poliésteres/química , Polietilenglicoles/química , Antineoplásicos/química , Antineoplásicos/metabolismo , Supervivencia Celular/efectos de los fármacos , Doxorrubicina/química , Doxorrubicina/metabolismo , Portadores de Fármacos/análisis , Portadores de Fármacos/metabolismo , Diseño de Fármacos , Endocitosis , Femenino , Citometría de Flujo , Células HeLa , Humanos , Concentración de Iones de Hidrógeno , Interacciones Hidrofóbicas e Hidrofílicas , Micelas , Oximas/metabolismo , Poliésteres/metabolismo , Polietilenglicoles/metabolismo , Neoplasias del Cuello Uterino/tratamiento farmacológico , Neoplasias del Cuello Uterino/patología
16.
Perfusion ; 26(3): 229-37, 2011 May.
Artículo en Inglés | MEDLINE | ID: mdl-21247985

RESUMEN

OBJECTIVES: This experiment sought to compare two polymethyl pentene (PMP) hollow-fiber membrane oxygenators: the Medos HILITE 2400 LT and the Maquet Quadrox-iD Pediatric in terms of transmembrane pressure gradients and hemodynamic energy preservation under both pulsatile and non-pulsatile conditions. METHODS: A simulated pediatric extracorporeal life support (ECLS) circuit was used to test these two oxygenators. The circuit consisted of a roller pump, » inch tubing for both arterial and venous lines, an oxygenator, and a venous reservoir served as a pseudo-patient. Three pressure transducers were placed upstream and downstream of the oxygenator and the distal arterial line. The experimental system was primed with lactated Ringer's solution and packed human red blood cells to maintain a hematocrit of 40%.The total volume was 600 ml, including the 350 ml volume of the pseudo-patient.The tests were performed at six flow rates (250, 500, 750, 1000, 1250, 1500 ml/min) and three distal arterial line pressures (MAP) (60, 80, 100 mmHg), under both pulsatile and non-pulsatile perfusion modes.The temperature was kept constant at 37°C for all tests. RESULTS: Both oxygenators had adequate performances in pressure drop and hemodynamic energy preservation. There were no significant differences between pre- and post-oxygenators for mean pressure (MP), energy equivalent pressure (EEP) and total hemodynamic energy (THE). During the pulsatile perfusion mode, the HILITE 2400 LT retained a greater percentage of surplus hemodynamic energy (SHE) across the oxygenator. CONCLUSIONS: Both the Quadrox-iD Pediatric and HILITE 2400LT PMP membrane oxygenators are suitable for pediatric ECLS therapy under both non-pulsatile and pulsatile perfusion. An optimized combination of flow rate and MAP should be achieved in order to deliver the maximal pulsatile energy in the extracorporeal circuit.


Asunto(s)
Oxigenación por Membrana Extracorpórea/métodos , Membranas Artificiales , Modelos Cardiovasculares , Oxigenadores de Membrana , Flujo Pulsátil , Niño , Preescolar , Femenino , Humanos , Masculino
17.
Langmuir ; 26(24): 19033-44, 2010 Dec 21.
Artículo en Inglés | MEDLINE | ID: mdl-21077617

RESUMEN

The microphase separation and morphology of a nearly symmetric A(0.3)B(0.3)C(0.4) star triblock copolymer thin film confined between two parallel, homogeneous hard walls have been investigated by self-consistent mean field theory (SCMFT) with a pseudospectral method. Our simulation experiments reveal that under surface confinement, in addition to the typically parallel, perpendicular, and tilted cylinders, other phases such as lamellae, perforated lamellae, and complex hybrid phases have been found to be stable, which is attributed to block-substrate interactions, especially for those hybrid phases in which A and B blocks disperse as spheres and alternately arrange as cubic CsCl structures, with a network preferred structure of C block. The results show that these hybrid phases are also stable within a broad hybrid region (H region) under a suitable film thickness and a broad field strength of substrates because their free energies are too similar to being distinguished. Phase diagrams have been evaluated by purposefully and systematically varying the film thickness and field strength for three different cases of Flory-Huggins interaction parameters between species in the star polymer. We also compare the phase diagrams for weak and strong preferential substrates, each with a couple of opposite quality, and discuss the influence of confinement, substrate preference, and the nature of the star polymer on the stability of relatively thinner and thick film phases in this work.


Asunto(s)
Modelos Moleculares , Polímeros/química , Conformación Molecular , Propiedades de Superficie , Termodinámica
18.
J Sci Food Agric ; 90(6): 1034-40, 2010 Apr 30.
Artículo en Inglés | MEDLINE | ID: mdl-20355144

RESUMEN

BACKGROUND: As the largest producer and consumer of freshwater fish in the world, many people suffer from allergy for consuming freshwater fish in China. However, the allergen profiles of freshwater fish are rarely known. RESULTS: Parvalbumins (PVs) from the white muscle of silver carp (Hypophthalmichthy molitrix) were purified by ammonium sulfate fractionation and column chromatography including DEAE-Sepharose and Superdex 75. Three PV isoforms-PV-I, PV-II, and PV-III-were obtained and their molecular masses as estimated by tricine-sodium dodecyl sulfate-polyacrylamide gel electrophoresis were 12, 11, and 14 kDa, respectively. All the PVs could be detected by anti-frog PV monoclonal antibody. PV-I and PV-II were quite possibly glycoproteins, while PV-III was not glycosylated, as analyzed by periodic acid-Schiff (PAS) staining. Thermal stability revealed that PV-I and PV-II easily formed polymers, while these proteins were stable in a pH range of 4.0-10.0. A PV gene encoding 110 amino acid residues was cloned and it revealed high identity with PVs from other species of fish. CONCLUSION: Three isotypes of PV were purified to homogeneity and one distinct PV gene was cloned in silver carp white muscle.


Asunto(s)
Carpas , Proteínas de Peces/química , Músculo Esquelético/química , Parvalbúminas/química , Alérgenos/química , Alérgenos/genética , Alérgenos/aislamiento & purificación , Secuencia de Aminoácidos , Animales , Anticuerpos Monoclonales , Secuencia de Bases , Carpas/genética , Clonación Molecular , Proteínas de Peces/genética , Proteínas de Peces/aislamiento & purificación , Glicosilación , Calor , Concentración de Iones de Hidrógeno , Datos de Secuencia Molecular , Parvalbúminas/genética , Parvalbúminas/aislamiento & purificación , Polímeros , Isoformas de Proteínas , Ranidae
19.
Chem Commun (Camb) ; 55(47): 6735-6738, 2019 Jun 06.
Artículo en Inglés | MEDLINE | ID: mdl-31119236

RESUMEN

A near-infrared (NIR)-sensitive gated assembly of supramolecular conjugated unimicelles based on robust host-guest recognition between a ß-cyclodextrin-grafted hyperbranched conjugated polymer and azobenzene-functionalized poly(ethylene glycol) was constructed. Utilized as a drug carrier, these unimicelles exhibited controlled drug release through the NIR-triggered photoisomerization of azobenzene in cancer cells via a two-photon excited fluorescence resonance energy transfer (TP-FRET) approach, leading to efficient cancer therapy.


Asunto(s)
Doxorrubicina/metabolismo , Portadores de Fármacos/química , Rayos Infrarrojos , Micelas , Compuestos Azo/química , Doxorrubicina/química , Liberación de Fármacos , Transferencia Resonante de Energía de Fluorescencia , Células HeLa , Humanos , Isomerismo , Microscopía Confocal , Fotones , Polietilenglicoles/química , Polímeros/química , beta-Ciclodextrinas/química
20.
Int J Biol Macromol ; 123: 50-58, 2019 Feb 15.
Artículo en Inglés | MEDLINE | ID: mdl-30391430

RESUMEN

As a kind of biomass that exists widely in plants, lignin shows much diversity as a functional material. In order to improve the adsorption ability, lignin was chemically modified by 5-sulfosalicylic acid and then used to adsorb methylene blue (MB) and Pb2+ from aqueous solutions. The results showed that the 5-sulfosalicylic acid modified lignin exhibited a high adsorption ability for dyes or heavy metals. The maximum adsorption capacity of the adsorbent approached 83.2 mg/g for MB and 39.3 mg/g for Pb2+ with the adsorbent dosage of 5 g/L at pH 5.85 or 5.35 (corresponding to MB or Pb2+, respectively), initial adsorbate concentration of 200 mg/L, temperature of 318 K and contact time of 12 h. The adsorption kinetics and isotherm studies indicated that both the adsorption of MB and Pb2+ onto SSAL followed the pseudo-second-order model and Langmuir isotherm model. It means that the adsorption process fits the model of mono-layer adsorption and it was mainly chemical process and accompanied with surface adsorption. The proposed SSAL is low-cost, eco-friendly and highly efficient therefore a promising material for adsorptive removal of MB and Pb2+ from wastewater.


Asunto(s)
Bencenosulfonatos/química , Plomo/química , Lignina/química , Azul de Metileno/química , Salicilatos/química , Adsorción , Biomasa , Cinética , Metales Pesados/química , Soluciones/química , Aguas Residuales/química , Agua/química , Contaminantes Químicos del Agua/química
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA