Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Resultados 1 - 20 de 28
Filtrar
1.
J Biol Chem ; 289(33): 22815-22834, 2014 Aug 15.
Artículo en Inglés | MEDLINE | ID: mdl-25008323

RESUMEN

A functional voltage-gated K(+) (Kv) channel comprises four pore-forming α-subunits, and only members of the same Kv channel subfamily may co-assemble to form heterotetramers. The ether-à-go-go family of Kv channels (KCNH) encompasses three distinct subfamilies: Eag (Kv10), Erg (Kv11), and Elk (Kv12). Members of different ether-à-go-go subfamilies, such as Eag and Erg, fail to form heterotetramers. Although a short stretch of amino acid sequences in the distal C-terminal section has been implicated in subfamily-specific subunit assembly, it remains unclear whether this region serves as the sole and/or principal subfamily recognition domain for Eag and Erg. Here we aim to ascertain the structural basis underlying the subfamily specificity of ether-à-go-go channels by generating various chimeric constructs between rat Eag1 and human Erg subunits. Biochemical and electrophysiological characterizations of the subunit interaction properties of a series of different chimeric and truncation constructs over the C terminus suggested that the putative C-terminal recognition domain is dispensable for subfamily-specific assembly. Further chimeric analyses over the N terminus revealed that the N-terminal region may also harbor a subfamily recognition domain. Importantly, exchanging either the N-terminal or the C-terminal domain alone led to a virtual loss of the intersubfamily assembly boundary. By contrast, simultaneously swapping both recognition domains resulted in a reversal of subfamily specificity. Our observations are consistent with the notion that both the N-terminal and the C-terminal recognition domains are required to sustain the subfamily-specific assembly of rat Eag1 and human Erg.


Asunto(s)
Canales de Potasio Éter-A-Go-Go/metabolismo , Animales , Canales de Potasio Éter-A-Go-Go/genética , Células HEK293 , Humanos , Estructura Cuaternaria de Proteína , Estructura Terciaria de Proteína , Ratas , Xenopus laevis
2.
Materials (Basel) ; 16(3)2023 Feb 02.
Artículo en Inglés | MEDLINE | ID: mdl-36770300

RESUMEN

Three sodium polyacrylate copolymers PD0x (Poly acrylic acid-co-sodium 4-vinylbenzenesulfonate or PD01; Poly acrylic acid-co-sodium 4-vinylbenzenesulfonate-co-hydroxyethyl methacrylate or PD02 and Poly methyl methacrylate-co-acrylic acid-co-sodium 4-vinylbenzenesulfonate-co-hydroxyethyl methacrylate or PD03) were synthesized as water-based dispersants for grinding red-brown pigment ZnFe1.2Cr0.8O4 particles prepared by the solid phase method (S-ZnF). The particle size distribution, viscosity of suspensions, and adsorption capacity of dispersants were explored by laser particle size analysis, viscometer, and thermogravimetry (TG), respectively. The application of 2 wt.% dispersant PD02 in the S-ZnF suspension ground for 90 min can deliver a finer product with the narrower particle size distribution. The added dispersant PD02 in the grinding process of the S-ZnF particles exhibits a suitable viscosity of the suspension and generates more hydrogen bonds on the S-ZnF particle surface. The sulfonic acid groups (SO3-) and carboxylic acid groups (-COO-) in the dispersant PD02 can also provide a strong charge density, which is favorable for the dispersion and grinding of the S-ZnF particles in the suspensions. Furthermore, the adsorption behavior of polymeric dispersant PD02 adsorbed on the S-ZnF particles surface was simulated and analyzed by adsorption thermodynamic models and adsorption kinetic models. It is indicated that the adsorption thermodynamic behavior of dispersant PD02 adsorbed on the S-ZnF particles surface follows the Langmuir model, and the adsorption process is endothermic and a random process with increased confusion during the grinding process. In addition, the adsorption kinetics of dispersant PD02 adsorbed on the S-ZnF particles surface are more in line with the pseudo-first-order kinetic models. Therefore, the adsorption process of dispersant PD02 on the S-ZnF particles surface can be considered as a single-surface adsorption process.

3.
J Am Chem Soc ; 134(37): 15201-4, 2012 Sep 19.
Artículo en Inglés | MEDLINE | ID: mdl-22946693

RESUMEN

Separation of hydrocarbons is one of the most energy demanding processes. The need to develop materials for the selective adsorption of hydrocarbons, under reasonable conditions, is therefore of paramount importance. This work unveils unexpected hydrocarbon selectivity in a flexible Metal-Organic Framework (MOF), based on differences in their gate opening pressure. We show selectivity dependence on both chain length and specific framework-gas interaction. By combining Raman spectroscopy and theoretical van der Waals Density Functional (vdW-DF) calculations, the separation mechanisms governing this unexpected gate-opening behavior are revealed.


Asunto(s)
Hidrocarburos/aislamiento & purificación , Metales/química , Compuestos Orgánicos/química , Adsorción , Espectrometría Raman
4.
Biomed Pharmacother ; 148: 112254, 2022 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-35183405

RESUMEN

BACKGROUND: Yiqi Tongluo Fang (YQTLF) is an effective prescription for the treatment of diabetic retinopathy (DR), but its mechanism of action remains unclear. METHOD: The content of YQTLF was determined using liquid and gas chromatography-mass spectrometry (LC-MS and GC-MS, respectively). Twenty-five Sprague Dawley (SD) rats were randomly selected as the normal control group. One hundred SD streptozotocin-induced diabetes (type 1) rats were randomly divided into diabetic control, diabetic+insulin+ calcium dobesilate (CaD), and diabetic+insulin+ YQTLF groups, with 25 rats in each group. Bodyweight level was measured every 2 weeks. After 12 weeks of gavage, the glucose levels, lipids, oxidative stress, inflammation, retinal histopathology, and the blood-retinal barrier were assessed in each group. The p38 MAPK pathway was changed to explore its internal mechanism. The measurement data were expressed as mean ± standard deviation, and different statistical methods were used according to a normal distribution, square error, or not. RESULTS: A total of 1024 valid peaks were identified in YQTLF using GC-MS. YQTLF significantly lowered the fasting blood glucose levels in diabetic rats. YQTLF early inhibited changes in retinal histology, capillaries, cells, and tight junction proteins (such as ZO-1, occludin, claudin-5, and VE-cadherin) before the formation and development of DR. These findings correlated with the alleviation of glucolipid metabolism, inflammation, and oxidative stress. The lncRNA MALAT1 and the PRC 2/p38 MAPK-related pathway, such as the expression of EZH2, SUZ12, EED, p38 MAPK, MMP-9, and VEGFR, were also correlated. CONCLUSION: We have demonstrated the molecular and cellular mechanisms underlying the preventive and delayed development and formation of DR. YQTLF prevents changes in dyslipidemia, retinal histology, capillaries, cells, and tight junction proteins. These protective effects appear to be linked to its antioxidant and anti-inflammatory effects, which prevent the activation of intracellular signaling pathways, such as the lncRNA MALAT1 and PRC 2/p38 MAPK-related pathway.


Asunto(s)
Diabetes Mellitus Experimental , Retinopatía Diabética , Animales , Antiinflamatorios/farmacología , Antiinflamatorios/uso terapéutico , Antioxidantes/farmacología , Antioxidantes/uso terapéutico , Diabetes Mellitus Experimental/tratamiento farmacológico , Retinopatía Diabética/tratamiento farmacológico , Retinopatía Diabética/metabolismo , Retinopatía Diabética/prevención & control , Medicamentos Herbarios Chinos , Ratas , Ratas Sprague-Dawley
5.
J Am Chem Soc ; 133(13): 4782-4, 2011 Apr 06.
Artículo en Inglés | MEDLINE | ID: mdl-21401134

RESUMEN

The role of low binding energy sites on the adsorption of H(2) in metal-organic frameworks (MOFs) with unsaturated metal centers has not been identified. For instance, the importance of the benzene sites on H(2) adsorption at the metal site in MOF-74 has not been established. We report here experimental evidence that unambiguously shows that the internal mode of H(2) adsorbed at the metal site undergoes both a frequency shift and a marked change in its dynamic dipole moment when H(2) is adsorbed at the next nearest neighbor "benzene" site in MOF-74-Co. The effect of loading (i.e., occupation of all benzene sites) also induces spectroscopic shifts in H(2) at the metal site. These interactions highlight the role of lower binding energy sites in H(2) adsorption.


Asunto(s)
Derivados del Benceno/química , Cobalto/química , Hidrógeno/química , Compuestos Organometálicos/química , Adsorción , Propiedades de Superficie
6.
J Am Chem Soc ; 133(32): 12849-57, 2011 Aug 17.
Artículo en Inglés | MEDLINE | ID: mdl-21736366

RESUMEN

The unusual uptake behavior and preferential adsorption of CO(2) over N(2) are investigated in a flexible metal-organic framework system, Zn(2)(bdc)(2)(bpee), where bpdc = 4,4'-biphenyl dicarboxylate and bpee = 1,2-bis(4-pyridyl)ethylene, using Raman and IR spectroscopy. The results indicate that the interaction of CO(2) with the framework induces a twisting of one of its ligands, which is possible because of the type of connectivity of the carboxylate end group of the ligand to the metal center and the specific interaction of CO(2) with the framework. The flexibility of the bpee pillars allows the structure to respond to the twisting, fostering the adsorption of more CO(2). DFT calculations support the qualitative picture derived from the experimental analysis. The adsorption sites at higher loading have been identified using a modified van der Waals-Density Functional Theory method, showing that the more energetically favorable positions for the CO(2) molecules are closer to the C═C bond of the bpee and the C-C bond of the bpdc ligands instead of the benzene and pyridine rings of these ligands. These findings are consistent with changes observed using Raman spectroscopy, which is useful for detecting both specific guest-host interactions and structural changes in the framework.

7.
J Transl Med ; 9: 82, 2011 May 28.
Artículo en Inglés | MEDLINE | ID: mdl-21619678

RESUMEN

BACKGROUND: Colorectal cancer (CRC) is the predominant gastrointestinal malignancy and the leading cause of cancer death. The identification of genes related to CRC is important for the development of successful therapies and earlier diagnosis. METHODS: Molecular analysis of feces was evaluated as a potential method for CRC detection. Expression of a predicted protein with unknown function, KIAA0247, was found in feces evaluated using specific quantitative real-time polymerase chain reaction. Its cellular function was then analyzed using immunofluorescent staining and the changes in the cell cycle in response to 5-fluorouracil (5-FU) were assessed. RESULTS: Gastrointestinal tissues and peripheral blood lymphocytes ubiquitously expressed KIAA0247. 56 CRC patients fell into two group categories according to fecal KIAA0247 mRNA expression levels. The group with higher fecal KIAA0247 (n=22; ≥0.4897) had a significantly greater five-year overall survival rate than the group with lower fecal KIAA0247 (n = 30; <0.4897) (66.0 ± 11.6%; p=0.035, log-rank test). Fecal expression of KIAA0247 inversely related to CRC tumor size (Kendall's tau-b=-0.202; p=0.047). Immunofluorescent staining revealed that the cytoplasm of CRC cells evenly expresses KIAA0247 without 5-FU treatment, and KIAA0247 accumulates in the nucleus after 40 µM 5-FU treatment. In HCT116 p53(-/-) cells, which lack p53 cell cycle control, the proportion of cells in the G2/M phase was larger (13%) in KIAA0247-silent cells than in the respective shLuc control (10%) and KIAA0247-overexpressing cells (7%) after the addition of low dose (40 µM) 5-FU. Expression of three cyclin genes (cyclin A2, cyclin B1, and cyclin B2) also downregulated in the cells overexpressing KIAA0247. CONCLUSIONS: This is the first description of a linkage between KIAA0247 and CRC. The study's data demonstrate overexpression of KIAA0247 associates with 5-FU therapeutic benefits, and also identify the clinical significance of fecal KIAA0247 in CRC.


Asunto(s)
Ciclo Celular/efectos de los fármacos , Neoplasias Colorrectales/tratamiento farmacológico , Neoplasias Colorrectales/patología , Proteínas del Sistema Complemento/metabolismo , Fluorouracilo/farmacología , Fluorouracilo/uso terapéutico , Anciano , División Celular/efectos de los fármacos , Colon/efectos de los fármacos , Colon/metabolismo , Colon/patología , Neoplasias Colorrectales/genética , Proteínas del Sistema Complemento/genética , Ciclinas/genética , Ciclinas/metabolismo , Heces , Femenino , Fase G2/efectos de los fármacos , Regulación Neoplásica de la Expresión Génica/efectos de los fármacos , Células HCT116 , Humanos , Espacio Intracelular/efectos de los fármacos , Espacio Intracelular/metabolismo , Masculino , Proteínas de la Membrana , Transporte de Proteínas/efectos de los fármacos , ARN Mensajero/genética , ARN Mensajero/metabolismo , Análisis de Supervivencia
8.
Chemistry ; 17(18): 5101-9, 2011 Apr 26.
Artículo en Inglés | MEDLINE | ID: mdl-21433121

RESUMEN

Hydroxyl- and amino- functionalized [Zn(BDC)(TED)(0.5)]·2DMF·0.2H(2)O leads to two new structures, [Zn(BDC-OH)(TED)(0.5)]·1.5DMF·0.3H(2)O and [Zn(BDC-NH(2))(TED)(0.5)]·xDMF·yH(2)O (BDC=terephthalic acid, TED=triethylenediamine, BDC-OH=2-hydroxylterephthalic acid, BDC-NH(2)=2-aminoterephthalic acid). Single-crystal X-ray diffraction and powder X-ray diffraction studies confirmed that the structures of both functionalized compounds are very similar to that of their parent structure. Compound [Zn(BDC)(TED)(0.5)]·2DMF·0.2H(2)O can be considered a 3D porous structure with three interlacing 1D channels, whereas both [Zn(BDC-OH)(TED)(0.5)]·1.5DMF·0.3H(2)O and [Zn(BDC-NH(2))(TED)(0.5)]·xDMF·yH(2)O contain only 1D open channels as a result of functionalization of the BDC ligand by the OH and NH(2) groups. A notable decrease in surface area and pore size is thus observed in both compounds. Consequently, [Zn(BDC)(TED)(0.5)]·2DMF·0.2H(2)O takes up the highest amount of H(2) at low temperatures. Interestingly, however, both [Zn(BDC-OH)(TED)(0.5)]·1.5DMF·0.3H(2)O and [Zn(BDC-NH(2))(TED)(0.5)]·xDMF·yH(2)O show significant enhancement in CO(2) uptake at room temperature, suggesting that the strong interactions between CO(2) and the functionalized ligands, indicating that surface chemistry, rather than porosity, plays a more important role in CO(2) adsorption. A comparison of single-component CO(2), CH(4), CO, N(2), and O(2) adsorption isotherms demonstrates that the adsorption selectivity of CO(2) over other small gases is considerably enhanced through functionalization of the frameworks. Infrared absorption spectroscopic measurements and theoretical calculations are also carried out to assess the effect of functional groups on CO(2) and H(2) adsorption potentials.


Asunto(s)
Dióxido de Carbono/farmacocinética , Modelos Moleculares , Compuestos Organometálicos/química , Ácidos Ftálicos/química , Zinc/química , Adsorción , Dióxido de Carbono/análisis , Cristalografía por Rayos X , Gases/química , Ligandos , Espectroscopía Infrarroja por Transformada de Fourier
9.
Langmuir ; 27(23): 14169-79, 2011 Dec 06.
Artículo en Inglés | MEDLINE | ID: mdl-21973224

RESUMEN

The intriguing hysteretic adsorption-desorption behavior of certain microporous metal-organic frameworks (MMOFs) has received considerable attention and is often associated with a gate-opening (GO) effect. Here, the hysteretic adsorption of N(2) and Ar to Zn(2)(bpdc)(2)(bpee) (bpdc = 4,4'-biphenyldicarboxylate; bpee = 1,2-bipyridylethene) shows a pronounced effect of allowed experimental time at 77 and 87 K. When the time allowed is on the order of minutes for N(2) at 77 K, no adsorption is observed, whereas times in excess of 60 h is required to achieve appreciable adsorption up to a limiting total coverage. Given sufficient time, the total uptake for N(2) and Ar converged at similar reduced temperatures, but the adsorption of Ar was significantly more rapid than that of N(2), an observation that can be described by activated configurational diffusion. N(2) and Ar both exhibited discontinuous stepped adsorption isotherms with significant hysteresis, features that were dependent upon the allowed time. The uptake of H(2) at 77 K was greater than for both N(2) and Ar but showed no discontinuity in the isotherm, and hysteretic effects were much less pronounced. N(2) and Ar adsorption data can be described by an activated diffusion process, with characteristic times leading to activation energies of 6.7 and 12 kJ/mol. Fits of H(2) adsorption data led to activation energies in the range 2-7 kJ/mol at low coverage and nonactivated diffusion at higher coverage. An alternate concentration-dependent diffusion model is presented to describe the stepwise adsorption behavior, which is observed for N(2) and Ar but not for H(2). Equilibrium is approached very slowly for adsorption to molecularly sized pores at low temperature, and structural change (gate opening), although it may occur, is not required to explain the observations.


Asunto(s)
Argón/química , Hidrógeno/química , Nitrógeno/química , Compuestos Organometálicos/química , Temperatura , Adsorción , Cinética , Propiedades de Superficie , Factores de Tiempo
10.
Inorg Chem ; 50(1): 208-12, 2011 Jan 03.
Artículo en Inglés | MEDLINE | ID: mdl-21141851

RESUMEN

A gallium-based metal-organic framework Ga(6)(C(9)H(3)O(6))(8)·(C(2)H(8)N)(6)(C(3)H(7)NO)(3)(H(2)O)(26) [1, Ga(6)(1,3,5-BTC)(8)·6DMA·3DMF·26H(2)O], GaMOF-1; BTC = benzenetricarboxylate/trimesic acid and DMA = dimethylamine], with space group I43d, a = 19.611(1) Å, and V = 7953.4(6) Å(3), was synthesized using solvothermal techniques and characterized by synchrotron-based X-ray microcrystal diffraction. Compound 1 contains isolated gallium tetrahedra connected by the organic linker (BTC) forming a 3,4-connected anionic porous network. Disordered positively charged ions and solvent molecules are present in the pore, compensating for the negative charge of the framework. These positively charged molecules could be exchanged with alkali-metal ions, as is evident by an ICP-MS study. The H(2) storage capacity of the parent framework is moderate with a H(2) storage capacity of ~0.5 wt % at 77 K and 1 atm.

11.
J Vet Intern Med ; 35(4): 1663-1672, 2021 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-33993546

RESUMEN

BACKGROUND: Point-of-care (POC) N-terminal pro B-type natriuretic peptide (NT-proBNP) ELISA test has been evaluated for screening cats for cardiac disease in the referral veterinary setting but less is known about its use in general practice (GP). OBJECTIVES: To evaluate the diagnostic utility of a POC NT-proBNP ELISA in cats seen in GPs. ANIMALS: Two hundred and seventeen apparently healthy cats from 21 GPs. METHODS: This was a prospective, cross-sectional study. Cardiac auscultation and POC NT-proBNP ELISA were done by veterinarians at their GPs. After enrollment at GPs, cats were sent to a cardiology referral hospital for cardiac auscultation and echocardiographic diagnosis. Results were interpreted based on whether cats had normal or abnormal echocardiographic findings. RESULTS: Point-of-care NT-proBNP ELISA results differentiated cats in the abnormal group from those in the normal group with a sensitivity of 43%, specificity of 96%. In cats with a heart murmur at GPs, POC NT-proBNP ELISA results differentiated cats in the abnormal group from those in the normal group with a sensitivity of 71% and a specificity of 92%. CONCLUSION AND CLINICAL IMPORTANCE: In apparently healthy cats in GPs, positive POC NT-proBNP results are associated with heart disease, warranting an echocardiogram, but negative results do not reliably exclude heart disease. These results suggest POC NT-proBNP is not an effective screening test for apparently healthy cats in GPs, although its performance is improved if it is used only in cats that have a heart murmur.


Asunto(s)
Enfermedades de los Gatos , Medicina General , Cardiopatías , Insuficiencia Cardíaca , Animales , Biomarcadores , Enfermedades de los Gatos/diagnóstico , Gatos , Estudios Transversales , Cardiopatías/diagnóstico , Cardiopatías/veterinaria , Insuficiencia Cardíaca/veterinaria , Péptido Natriurético Encefálico , Fragmentos de Péptidos , Sistemas de Atención de Punto , Estudios Prospectivos
12.
J Am Chem Soc ; 132(42): 14834-48, 2010 Oct 27.
Artículo en Inglés | MEDLINE | ID: mdl-20925338

RESUMEN

Infrared (IR) absorption spectroscopy measurements of molecular hydrogen in MOF-74-M (M = metal center) are performed as a function of temperature and pressure [to 45 kTorr (60 bar) at 300 K, and at lower pressures in the 20-200 K range] to investigate the nature of H(2) interactions with the unsaturated metal centers. A small shift (∼ -30 cm(-1) with respect to the unperturbed H(2) molecule) is observed for the internal stretch frequency of H(2) molecules adsorbed on the metal site at low loading. This finding is in contrast to much larger shifts (∼ -70 cm(-1)) observed in previous studies of MOFs with unsaturated metal centers (including MOF-74) and the general assumption that H(2) stretch shifts depend on adsorption energies (FitzGerald et al., Phys. Rev. B 2010, 81, 104305). We show that larger shifts (∼ -70 cm(-1)) do occur, but only when the next available site ("oxygen" site) is occupied. This larger shift originates from H(2)-H(2) interactions on neighboring sites of the same pore, consistent with the short distance between H(2) in these two sites ∼2.6 Šderived from an analysis of neutron diffraction experiments of D(2)-D(2) at 4 K (Liu et al., Langmuir 2008, 24, 4772-4777). Our results at 77 K and low loading can be explained by a diffusion barrier against pair disruption, which should be enhanced by this interaction. Calculations indicate that the vibrational shifts do not correlate with binding energies and are instead very sensitive to the environment (interaction potential and H(2)-H(2) interactions), which complicates the use of variable temperature IR methods to calculate adsorption energies of specific adsorption sites.

13.
Theranostics ; 10(22): 10092-10105, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-32929336

RESUMEN

Rheumatoid arthritis (RA), a common inflammatory disorder of the joints characterized by synovitis and pannus formation, often results in irreversible joint erosion and disability. Methotrexate (MTX) is the first-line drug against RA, but the therapeutic effects are sub-optimal due to its poor retention at the target sites and systemic side effects. Multifunctional nanoparticles are highly promising agents for minimally invasive, traceable and effective targeted therapy. Methods: This study developed iRGD peptide-functionalized echogenic liposomes (iELPs) which encapsulates MTX and indocyanine green (ICG) fluorescent probe through the thin film-hydration method. Results: The resulting iELPs showed high affinity for endothelial cells overexpressing αvß3 integrin, favorable acoustic response and fluorescence tracking properties. Also, near-infrared (NIR) fluorescence imaging of iELPs and ultrasound-triggered drug release of MTX were proved in a mouse RA model, greatly improving the therapeutic efficacy and reducing MTX side effects. Histological assessment of the articular tissues further revealed significantly lower inflammatory cell infiltration and angiogenesis in the iELPs-treated and sonicated mice. Conclusion: Our study provides a promising nanoplatform for integrating ultrasound-controlled drug release and NIR fluorescence imaging for RA treatment.


Asunto(s)
Artritis Reumatoide/tratamiento farmacológico , Colorantes Fluorescentes/administración & dosificación , Liposomas/metabolismo , Metotrexato/farmacología , Oligopéptidos/farmacología , Imagen Óptica/métodos , Terapia por Ultrasonido/métodos , Animales , Línea Celular , Células Endoteliales/efectos de los fármacos , Células Endoteliales/metabolismo , Células Endoteliales de la Vena Umbilical Humana , Humanos , Verde de Indocianina/metabolismo , Integrina alfaVbeta3/metabolismo , Masculino , Ratones , Células RAW 264.7 , Espectroscopía Infrarroja Corta/métodos , Porcinos , Ondas Ultrasónicas
14.
J Am Chem Soc ; 131(20): 6894-5, 2009 May 27.
Artículo en Inglés | MEDLINE | ID: mdl-19453189

RESUMEN

The tetracarboxylate organic linker and Zn(II) ions assemble into chiral building blocks for a porous metal-organic framework with ferroelectric and second-order nonlinear optical properties.

15.
Inorg Chem ; 48(15): 7165-73, 2009 Aug 03.
Artículo en Inglés | MEDLINE | ID: mdl-19722690

RESUMEN

A microporous metal organic framework structure, Zn(2)(bpdc)(2)(bpee).2DMF (DMF: N,N-dimethylformamide), has been synthesized via solvothermal reactions. The compound is a new member of the RPM series (RPM = Rutgers Recyclable Porous Material) that possesses a flexible and recyclable three-dimensional framework containing one-dimensional channels. It exhibits interesting and multifold functionality, including porosity, commensurate adsorption for hydrocarbons, high hydrogen binding energy (determined by isosteric heats of hydrogen adsorption and confirmed by van der Waals density functional calculations) as a result of multifold binding to aromatic ligands (determined by IR spectroscopy), strong photoluminescence emission, and reversible fluorescence quenching properties.

17.
Angew Chem Int Ed Engl ; 48(13): 2334-8, 2009.
Artículo en Inglés | MEDLINE | ID: mdl-19180622

RESUMEN

Sensors and sensitivity: A highly luminescent microporous metal-organic framework, [Zn(2)(bpdc)(2)(bpee)] (bpdc = 4,4'-biphenyldicarboxylate; bpee = 1,2-bipyridylethene), is capable of very fast and reversible detection of the vapors of the nitroaromatic explosive 2,4-dinitrotoluene and the plastic explosive taggant 2,3-dimethyl-2,3-dinitrobutane, through redox fluorescence quenching with unprecedented sensitivity (see spectra).

18.
Int J Nanomedicine ; 13: 1841-1850, 2018.
Artículo en Inglés | MEDLINE | ID: mdl-29615837

RESUMEN

BACKGROUND: Rheumatoid arthritis (RA) is a common inflammatory disorder characterized primarily by synovitis and pannus formation in multiple joints, causing joints destruction and irreversible disability in most cases. Early diagnosis and effective therapy monitoring of RA are of importance for achieving the favorable prognosis. METHODS: We first prepared the targeted fluorescence probes, and then explored the feasibility of near-infrared (NIR) fluorescence molecular imaging to detect and evaluate the RA via the targeted fluorescence probes by quantitative analysis in this study. RESULTS: The targeted fluorescence probes (indocyanine green-liposomes decorated with iRGD peptide [iLPs]) was successfully prepared. The quantitative analysis found that strong fluorescence signal was detected in inflamed paws and the fluorescence signal in iLPs group was 3.03-fold higher than that in non-targeted (indocyanine green-liposomes decorated without iRGD peptide [LPs]) group (P<0.01) at 15 min after injection, whereas the fluorescence signal from iLPs signal can almost not be observed in the non-inflamed paws, showing the high sensitivity and accuracy for arthritis by the NIR fluorescence imaging based on iLPs. CONCLUSION: The NIR fluorescence imaging by iLPs may facilitate improved arthritis diagnosis and early assessment of the disease progression by providing an in vivo characterization of angiogenesis in inflammatory joint diseases.


Asunto(s)
Artritis Reumatoide/diagnóstico por imagen , Colorantes Fluorescentes/química , Liposomas/administración & dosificación , Imagen Molecular/métodos , Sinovitis/diagnóstico por imagen , Animales , Artritis Reumatoide/complicaciones , Colorantes Fluorescentes/farmacocinética , Colorantes Fluorescentes/uso terapéutico , Células Endoteliales de la Vena Umbilical Humana , Humanos , Verde de Indocianina/química , Liposomas/química , Liposomas/farmacocinética , Masculino , Ratones Endogámicos DBA , Oligopéptidos , Imagen Óptica/métodos , Sinovitis/etiología , Distribución Tisular
20.
Nan Fang Yi Ke Da Xue Xue Bao ; 37(10): 1283-1289, 2017 Oct 20.
Artículo en Zh | MEDLINE | ID: mdl-29070455

RESUMEN

OBJECTIVE: To prepare internalized RGD (iRGD) modified echogenic liposomes containing methotrexate (MTX) and indocyanine green (ICG) (iRGD MTX ICG ELIP) and evaluate its targeting efficiency and inhibitory effect combined with ultrasound on synovial cells. METHODS: iRGD MTX ICG ELIP was prepared by the thin film rehydration and freeze-lyophilization method and its general characteristics and acoustic responsiveness were assessed. The targeting effect of the prepared liposome was observed by assessing its cell uptake in vitro. In a mouse model of rheumatiod arthritis, the targeting effect of the prepared liposome was determined by detecting the fluorescence intensity of the drug in arthrosis. The inhibitory effect of iRGD MTX ICG ELIP combined with ultrasound on synovial MH7A cells in vitro were investigated using CCK8 test. RESULTS: The average diameter and zeta potential of iRGD MTX ICG ELIP was 134.4∓17.61 nm and 10.07∓4.28 mV, and the entrapment efficiency of MTX and ICG was (62.56∓0.77)% and (95.13∓0.82)%, respectively. With ultrasound exposure, the release of MTX and ICG from iRGD MTX ICG ELIP increased with the ultrasound intensity and with the exposure time. In HUVECs, the uptake efficiency of iRGD MTX ICG ELIP was 1.89 times higher than that of non targeted MTX ICG ELIP (P<0.05). In vivo imaging of mouse joint with rheumatiod arthritis showed that the fluorescence intensity of iRGD MTX ICG ELIP was significantly stronger than that of the non targeted liposome. CCK8 assay showed that iRGD MTX ICG ELIP combined with ultrasound resulted in a survival rate of MH7A cells of (32.49∓3.04)%, significantly lower than the rate of cells treated with iRGD MTX ICG ELIP but without ultrasound (P<0.05). CONCLUSIONS: iRGD MTX ICG ELIP has a suitable particle size and can effectively target HUVECs and the joints with rheumatiod arthritis. With a good drug entrapment efficiency and acoustic responsiveness, the drug loaded liposome shows enhanced inhibitory effect on MH7A cells combined with ultrasound in vitro, suggesting its potential in the treatment of rheumatoid arthritis.


Asunto(s)
Artritis Reumatoide/diagnóstico por imagen , Artritis Reumatoide/tratamiento farmacológico , Liposomas/química , Metotrexato/farmacología , Oligopéptidos/química , Animales , Células Endoteliales de la Vena Umbilical Humana , Humanos , Verde de Indocianina , Ratones , Tamaño de la Partícula , Ultrasonografía
SELECCIÓN DE REFERENCIAS
Detalles de la búsqueda