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1.
Artigo em Inglês | MEDLINE | ID: mdl-32029275

RESUMO

AIMS: Endothelial progenitor cells (EPCs) are widely accepted to be applied in ischemic diseases. However, the therapeutic potency is largely impeded because of its inviability in these ischemic conditions. Autophagy is recognized to be vital in cell activity. Therefore, we explore the role and the mechanism of autophagy in ischemic EPCs. METHODS AND RESULTS: We applied 7d-cultured bone marrow EPCs to investigate the autophagy status under the oxygen and glucose deprivation (OGD) conditions in vitro, mimicking the in-vivo harsh ischemia and anoxia microenvironment. We found increased EPC apoptosis, accompanied by an impaired autophagy activation. Intriguingly, mTOR inhibitor Rapamycin was incapable to reverse this damped autophagy and EPC damage. We further found that autophagy pathway downstream Vps34-Beclin1-Atg14 complex assembly and activity were impaired in OGD conditions, and an autophagy-inducing peptide Tat-Beclin1 largely recovered the impaired complex activity and attenuated OGD-stimulated EPC injury through restoring autophagy activation. CONCLUSIONS: The present study discovered that autophagy activation is inhibited when EPCs located in the ischemia and anoxia conditions. Restoration of Vps34 complex activity obtains sufficient autophagy, thus promoting EPC survival, which will provide a potential target and advance our understanding of autophagy manipulation in stem cell transplantation.

2.
Zhonghua Yi Xue Yi Chuan Xue Za Zhi ; 36(9): 870-873, 2019 Sep 10.
Artigo em Chinês | MEDLINE | ID: mdl-31515778

RESUMO

OBJECTIVE: To assess the value of dry blood spot tandem mass spectrometry for the diagnosis of autism spectrum disorder (ASD). METHODS: Peripheral blood samples of 277 autistic children were collected. Their amino acid and carnitine profiles were detected by liquid chromatography tandem mass spectrometry. Urine samples of suspected patients were collected for verification by gas chromatography mass spectrometry. Blood samples were also taken for genetic testing. RESULTS: Of the 277 children with ASD, 19 (6.9%) were suspected to be with inborn error of metabolism (IEM), which included 6 cases with amino acidemia, 9 with organic acidemia and 4 with fatty acidemia. Three cases of phenylketonuria, one case of homocysteinemia, one case of propionemia, one case of methylmalonic acidemia, one case of glutaric acidemia, one case of isovaleric acidemia, one case of argininemia, one case of citrullinemia I and four cases of primary carnitine deficiency were confirmed by genetic testing, which yielded an overall diagnostic rate of 5.1% (14/277). CONCLUSION: Our result has provided further evidence for the co-occurrence of ASD and IEM. Tandem mass spectrometry has a great value for the diagnosis and treatment of ASD in childhood.


Assuntos
Transtorno do Espectro Autista/diagnóstico , Erros Inatos do Metabolismo/diagnóstico , Erros Inatos do Metabolismo dos Aminoácidos/complicações , Erros Inatos do Metabolismo dos Aminoácidos/diagnóstico , Transtorno do Espectro Autista/complicações , Criança , Teste em Amostras de Sangue Seco , Cromatografia Gasosa-Espectrometria de Massas , Humanos , Erros Inatos do Metabolismo/complicações , Espectrometria de Massas em Tandem
3.
J Fluoresc ; 26(6): 2005-2013, 2016 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-27484984

RESUMO

A series of ß-diketone derivatives bearing tetraphenylene (TPE) moieties were synthesized and characterized. Their photophysical properties were investigated systematically via spectroscopic and theoretical methods. All compounds exhibit broad absorption bands between 300 and 450 nm, which are assigned to the 1π-π* transition of the conjugated system mixed intramolecular charge-transfer (ICT) transitions. Meanwhile, the emission of these compounds in solution at room temperature (λ em = 458 ~ 509 nm) can be attributed to the 1π,π*/1ICT state. Introduction of freely rotatable TPE to conventional ß-diketone luminophors quenches their light emissions in the solutions, but endows these molecules with aggregation-induced emission (AIE) characteristics in the condensed phase due to the restriction of intramolecular rotation. The spectroscopic studies and theoretical calculations indicate that the photophysical properties of these ß-diketone derivatives can be tuned by the appended substituents, which would be useful for rational design of AIE compounds with high solid state luminescence performance. Furthermore, these AIE-active compounds exhibited distinct piezofluorochromic properties and switched reversibly upon grinding-fuming. Their photophysical properties have been investigated with the aim to provide a basis for elucidating the structure-property correlations and developing new multi-stimuli responsive luminescent materials.

4.
J Mol Graph Model ; 59: 31-9, 2015 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-25899446

RESUMO

The heterocyclic urea of deazapterin (DeAPa) and its protomeric conformers (b, c) with different substituents are selected as the building block for a series of dimers in different configurations. The stabilities of all dimers in various conditions have been investigated by density functional theory. Homodimer of b has more stability than other dimers. Topological analyses certify the coexistence of intermolecular with intramolecular H-bonds. Investigations into frequency demonstrate that all H-bonds show an evident red shift in their stretching vibrational frequencies. Electron donating substituents can provide favorable free energies of the dimer. Solvent effect computations suggest that the dimerization can be favored in weakly polar solvents, such as toluene and chloroform. UV-visible spectra exhibit obvious difference of maximum absorption wavelengths between monomers and dimers, thus may have potential applications for identifying intermolecular H-bonds and calculating association constant of DeAP equilibrium systems in experiments.


Assuntos
Hidrogênio/química , Polímeros/química , Simulação por Computador , Dimerização , Elétrons , Ligações de Hidrogênio , Modelos Moleculares , Teoria Quântica , Solventes/química , Vibração
5.
J Mol Model ; 20(7): 2335, 2014 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-25007917

RESUMO

The trans-2-chlorovinyldichloroarsine (Lewisite) was produced and handled during WWI and WWII as chemical warfare agents. It was very difficult to explore its chemical characterization by experiments ways. The quantum chemical calculations proved to be a precise and harmless method for the toxicological system. In this paper, the gas phase reaction mechanisms of OH radical with trans-2-chlorovinyldichloroarsine (lewisite) were studied by second-order Møller-Plesset perturbation theory (MP2) method. The geometries of reactants, products, complexes, and transition states were optimized at the MP2/6-311++G(d,p) level. To gain more accurate mechanistic knowledge, the single-point energies were calculated using G3 and CCSD(T) method. This reaction exhibited three mechanisms, namely, direct hydrogen abstraction, direct chlorine abstraction, and addition/elimination. Multichannel Rice-Ramsperger-Kassel-Marcus theory and transition-state theory have been carried out for overall and individual rate constants over a wide range of temperatures and pressures. The computational results indicated that addition/elimination reaction is more favorable than direct hydrogen abstraction and direct chlorine abstraction. The major products for the total reaction are AsCl2 and CHClCH2O generated via C(2)-addition/elimination.

6.
Chemphyschem ; 15(9): 1772-8, 2014 Jun 23.
Artigo em Inglês | MEDLINE | ID: mdl-24954437

RESUMO

Porous aromatic frameworks (PAFs) are novel materials with diamond topology. With the aim of enhancing their CO(2) capture and storage capacity and investigating the effect of nitrogen and/or -COOH decorations on CO(2) adsorption in PAFs, a series of N-containing PAFs were designed based on ab initio results. The interaction energies (E(int)) between CO(2) and each six-membered ring were calculated at the B2PLYP-D2/def2-TZVPP level, then the six-membered rings with high CO(2) -binding affinity were selected and used in the PAFs. To explore the performance of the designed PAFs, the CO(2) uptake, selectivity of CO(2) over CH(4), H(2), and N(2), and the E(int) value of CO(2) in PAFs were investigated by using grand canonical Monte Carlo (GCMC) simulations and ab initio calculations. This work shows that pyridine with one nitrogen atom can provide a strong physisorption site for CO(2), whereas more nitrogen atoms in heterocycles will reduce the interaction, especially at relatively low pressure. PAFs with -COOH groups show high CO(2) capacity. Our work provides an efficient way to understand the adsorption mechanism and a supplemental approach to experimental work.

7.
J Chem Phys ; 140(8): 084309, 2014 Feb 28.
Artigo em Inglês | MEDLINE | ID: mdl-24588171

RESUMO

The reaction of allyl chloride with the hydroxyl radical has been investigated on a sound theoretical basis. This is the first time to gain a conclusive insight into the reaction mechanism and kinetics for important pathways in detail. The reaction mechanism confirms that OH addition to the C=C double bond forms the chemically activated adducts, IM1 (CH2CHOHCH2Cl) and IM2 (CH2OHCHCH2Cl) via low barriers, and direct H-abstraction paths may also occur. Variational transition state model and multichannel RRKM theory are employed to calculate the temperature-, pressure-dependent rate constants. The calculated rate constants are in good agreement with the experimental data. At 100 Torr with He as bath gas, IM6 formed by collisional stabilization is the major products in the temperature range 200-600 K; the production of CH2CHCHCl via hydrogen abstractions becomes dominant at high temperatures (600-3000 K).


Assuntos
Compostos Alílicos/química , Gases/química , Radical Hidroxila/química , Teoria Quântica , Pressão , Temperatura Ambiente
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