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1.
Artigo em Inglês | MEDLINE | ID: mdl-38693081

RESUMO

PURPOSE: The aim of the study is to investigate the feasibility of using dual-source computed tomography (CT) combined with low flow rate and low tube voltage for postchemotherapy image assessment in cancer patients. METHODS: Ninety patients undergoing contrast-enhanced CT scans of the upper abdomen were prospectively enrolled and randomly assigned to groups A, B, and C (n = 30 each). In group A, patients underwent scans at 120 kVp with 448 mgI/kg. Patients in group B underwent scans at 100 kVp with 336 mgI/kg. Patient in group C underwent scans at 70 kVp with of 224 mgI/kg. Quantitative measurements including the CT number, standard deviation of CT number, signal-to-noise ratio, contrast-to-noise ratio, subjective reader scores, and the volume and flow rate of contrast agent were evaluated for each group. RESULTS: There was no statistically significant difference in the subjective image scores within the three groups except for the kidney (all P > 0.05). Group C showed significantly higher CT values, lower noise levels, and higher signal-to-noise ratio and contrast-to-noise ratio values in the majority of the regions of interest compared to the other groups (P < 0.05). In group C, the contrast agent dose was decreased by 46% compared to group A (79.48 ± 12.24 vs 42.7 ± 8.6, P < 0.01), and the contrast agent injection rate was reduced by 22% (2.7 ± 0.41 vs 2.1 ± 0.4, P < 0.01). CONCLUSIONS: The use of 70 kVp tube voltage combined with low iodine flow rates prove to be a more effective approach in solving the challenge of compromised blood vessels in postchemotherapy tumor patients, without reducing image quality and diagnostic confidence.

2.
ACS Biomater Sci Eng ; 10(5): 3268-3279, 2024 05 13.
Artigo em Inglês | MEDLINE | ID: mdl-38659167

RESUMO

The self-assembly of collagen within the human body creates a complex 3D fibrous network, providing structural integrity and mechanical strength to connective tissues. Recombinant collagen plays a pivotal role in the realm of biomimetic natural collagen. However, almost all of the reported recombinant collagens lack the capability of self-assembly, severely hindering their application in tissue engineering and regenerative medicine. Herein, we have for the first time constructed a series of self-assembling tyrosine-rich triple helix recombinant collagens, mimicking the structure and functionality of natural collagen. The recombinant collagen consists of a central triple-helical domain characterized by the (Gly-Xaa-Yaa)n sequence, along with N-terminal and C-terminal domains featuring the GYY sequence. The introduction of GYY has a negligible impact on the stability of the triple-helical structure of recombinant collagen while simultaneously promoting its self-assembly into fibers. In the presence of [Ru(bpy)3]Cl2 and APS as catalysts, tyrosine residues in the recombinant collagen undergo covalent cross-linking, resulting in a hydrogel with exceptional mechanical properties. The recombinant collagen hydrogel exhibits outstanding biocompatibility and bioactivity, significantly enhancing the proliferation, adhesion, migration, and differentiation of HFF-1 cells. This innovative self-assembled triple-helix recombinant collagen demonstrates significant potential in the fields of tissue engineering and medical materials.


Assuntos
Colágeno , Hidrogéis , Proteínas Recombinantes , Tirosina , Tirosina/química , Humanos , Colágeno/química , Hidrogéis/química , Proteínas Recombinantes/química , Proliferação de Células/efeitos dos fármacos , Adesão Celular/efeitos dos fármacos , Engenharia Tecidual/métodos , Linhagem Celular , Movimento Celular/efeitos dos fármacos , Diferenciação Celular/efeitos dos fármacos , Materiais Biocompatíveis/química
3.
Angew Chem Int Ed Engl ; 63(17): e202316551, 2024 Apr 22.
Artigo em Inglês | MEDLINE | ID: mdl-38411372

RESUMO

Single-entity electrochemistry is a powerful tool that enables the study of electrochemical processes at interfaces and provides insights into the intrinsic chemical and structural heterogeneities of individual entities. Signal processing is a critical aspect of single-entity electrochemical measurements and can be used for data recognition, classification, and interpretation. In this review, we summarize the recent five-year advances in signal processing techniques for single-entity electrochemistry and highlight their importance in obtaining high-quality data and extracting effective features from electrochemical signals, which are generally applicable in single-entity electrochemistry. Moreover, we shed light on electrochemical noise analysis to obtain single-molecule frequency fingerprint spectra that can provide rich information about the ion networks at the interface. By incorporating advanced data analysis tools and artificial intelligence algorithms, single-entity electrochemical measurements would revolutionize the field of single-entity analysis, leading to new fundamental discoveries.

4.
Front Plant Sci ; 14: 1293374, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-38023879

RESUMO

Highly efficient genetic transformation technology is beneficial for plant gene functional research and molecular improvement breeding. However, the most commonly used Agrobacterium tumefaciens-mediated genetic transformation technology is time-consuming and recalcitrant for some woody plants such as citrus, hampering the high-throughput functional analysis of citrus genes. Thus, we dedicated to develop a rapid, simple, and highly efficient hairy root transformation system induced by Agrobacterium rhizogenes to analyze citrus gene function. In this report, a rapid, universal, and highly efficient hairy root transformation system in citrus seeds was described. Only 15 days were required for the entire workflow and the system was applicable for various citrus genotypes, with a maximum transformation frequency of 96.1%. After optimization, the transformation frequency of Citrus sinensis, which shows the lowest transformation frequency of 52.3% among four citrus genotypes initially, was increased to 71.4% successfully. To test the applicability of the hairy roots transformation system for gene functional analysis of citrus genes, we evaluated the subcellular localization, gene overexpression and gene editing in transformed hairy roots. Compared with the traditional transient transformation system performed in tobacco leaves, the transgenic citrus hairy roots displayed a more clear and specific subcellular fluorescence localization. Transcript levels of genes were significantly increased in overexpressing transgenic citrus hairy roots as compared with wild-type (WT). Additionally, hairy root transformation system in citrus seeds was successful in obtaining transformants with knocked out targets, indicating that the Agrobacterium rhizogenes-mediated transformation enables the CRISPR/Cas9-mediated gene editing. In summary, we established a highly efficient genetic transformation technology with non-tissue-culture in citrus that can be used for functional analysis such as protein subcellular localization, gene overexpression and gene editing. Since the material used for genetic transformation are roots protruding out of citrus seeds, the process of planting seedlings prior to transformation of conventional tissue culture or non-tissue-culture was eliminated, and the experimental time was greatly reduced. We anticipate that this genetic transformation technology will be a valuable tool for routine research of citrus genes in the future.

5.
Hortic Res ; 10(2): uhac256, 2023 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-36778181

RESUMO

Thioredoxins (TRXs) are ubiquitous oxidoreductases and present as a multigenic family. TRXs determine the thiol redox balance, which is crucial for plants in the response to cold stress. However, limited knowledge is available about the role of TRXs in watermelon (Citrullus lanatus), which is highly sensitive to chilling stress in agricultural practice. Here, we identified 18 genes encoding 14 typical and 4 atypical TRXs from the watermelon genome, and found that ClTRX h2 localized at the plasma membrane was largely induced by chilling. Virus-induced gene silencing of ClTRX h2 resulted in watermelon plants that were more sensitive to chilling stress. We further found that ClTRX h2 physically interacted with mitogen-activated protein kinase kinase 5 (ClMPKK5), which was confirmed to phosphorylate and activate ClMPK3 in vitro, and the activation of ClMPK3 by ClMPKK5 was blocked by a point mutation of the Cys-229 residue to Ser in ClMPKK5. Additionally, ClTRX h2 inhibited the chilling-induced activation of ClMPK3, suggesting that the ClMPKK5-ClMPK3 cascade is regulated in a redox-dependent manner. We showed that ClMPK3-silenced plants had increased tolerance to chilling, as well as enhanced transcript abundances of the C-repeat/DREB binding factor (ClCBF) and cold-responsive (ClCOR) genes. Taken together, our results indicate that redox status mediated by ClTRX h2 inhibits ClMPK3 phosphorylation through the interaction between ClTRX h2 and ClMPKK5, which subsequently regulates the CBF-COR signaling pathway when submitted to chilling stress. Hence, our results provide a link between thiol redox balance and MAPK cascade signaling, revealing a conceptual framework to understand how TRX regulates chilling stress tolerance in watermelon.

6.
Sensors (Basel) ; 22(17)2022 Sep 02.
Artigo em Inglês | MEDLINE | ID: mdl-36081107

RESUMO

The recognition of warheads in the target cloud of the ballistic midcourse phase remains a challenging issue for missile defense systems. Considering factors such as the differing dimensions of the features between sensors and the different recognition credibility of each sensor, this paper proposes a weighted decision-level fusion architecture to take advantage of data from multiple radar sensors, and an online feature reliability evaluation method is also used to comprehensively generate sensor weight coefficients. The weighted decision-level fusion method can overcome the deficiency of a single sensor and enhance the recognition rate for warheads in the midcourse phase by considering the changes in the reliability of the sensor's performance caused by the influence of the environment, location, and other factors during observation. Based on the simulation dataset, the experiment was carried out with multiple sensors and multiple bandwidths, and the results showed that the proposed model could work well with various classifiers involving traditional learning algorithms and ensemble learning algorithms.


Assuntos
Algoritmos , Simulação por Computador , Reprodutibilidade dos Testes
8.
Ann Palliat Med ; 9(2): 463-471, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-32233620

RESUMO

Whole-breast radiotherapy after breast-conserving surgery (BCS) can improve patient survival while reducing local tumor recurrence. Although standard breast radiotherapy can achieve good tumor control and cosmetic effects with low toxicity, the 5- to 7-week treatment time is relatively long for patients and can result in wasted medical resources. Therefore, there is a growing trend toward hypofractionated radiotherapy (HFRT), which accelerates partial-breast irradiation. Both short-course radiotherapy and conventional fractionated radiotherapy are safe and effective treatment modes, with similar survival and local tumor control effects as those of conventional radiotherapy (CRT), and adverse reactions can be tolerated. Compared with conventional fractionated radiotherapy, short-course radiotherapy saves medical resources and has a shorter total treatment time, reduced treatment costs, and an improved quality of life for patients.


Assuntos
Neoplasias da Mama/radioterapia , Recidiva Local de Neoplasia/prevenção & controle , Hipofracionamento da Dose de Radiação , Neoplasias da Mama/patologia , Feminino , Humanos , Mastectomia Segmentar , Estadiamento de Neoplasias , Dosagem Radioterapêutica , Radioterapia Adjuvante , Resultado do Tratamento
9.
J Surg Res ; 251: 180-186, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32155473

RESUMO

OBJECTIVE: To explore the distribution of biliary ductules in biliary remnants of patients with biliary atresia and to investigate the relationship between the ductules and the prognosis after Kasai portoenterostomy. PATIENTS AND METHODS: From October 01, 2015 to September 30, 2017, 46 patients who were diagnosed as type 3 biliary atresia were enrolled in this study. Continuous sections of biliary remnants were stained with cytokerantin 19 antibody. The number, area, and distribution of micro-biliary ductules of each section were recorded. According to the number of ductules in the most proximal section (n ≥ 20 or n < 20), patients were divided into two groups (A or B) and followed up for 1-3 y, including cholangitis, jaundice clearance, and survival with native liver. RESULTS: Four patients had no micro-biliary ductules. In 17 patients with ductules, the numbers at bilateral parts were similar (P > 0.05), while the ductules in the middle part were significantly less than bilateral parts (P < 0.05). Starting from 2 mm from the proximal end of remnants, the number of ductules significantly and gradually decreased (P < 0.05). The total area of ductules in Group A was significantly increased compared to that in Group B (P < 0.05). Patients in Group A had significantly higher jaundice clearance rate and better survival rate with native liver than patients in Group B (both, P < 0.05). Patients had significantly higher incidence of cholangitis in Group A compared to Group B (P < 0.05). CONCLUSIONS: The number/area of ductules yielded by technical precision is closely related to effective bile drainage, jaundice clearance, and first onset of cholangitis in patients after Kasai procedure.


Assuntos
Ductos Biliares/cirurgia , Atresia Biliar/cirurgia , Portoenterostomia Hepática , Ductos Biliares/patologia , Atresia Biliar/patologia , Feminino , Humanos , Lactente , Masculino
10.
Front Immunol ; 11: 580334, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33488582

RESUMO

Foot-and-mouth disease (FMD) is a severe, highly contagious viral disease of cloven-hoofed animals. In order to establish an infection, the FMD virus (FMDV) needs to counteract host antiviral responses. Tumor progression locus 2 (TPL2), a mitogen-activated protein kinase, can regulate innate and adaptive immunity; however, its exact mechanisms underlying TPL2-mediated regulation of the pathogenesis of FMDV infection remain unknown. In this study, we confirmed that TPL2 could inhibit FMDV replication in vitro and in vivo. The virus replication increased in Tpl2-deficient suckling mice in association with reduced expression of interferon-stimulated genes interferon-α (IFN-α) and myxovirus resistance (MX2) and significantly reduced expression of C-X-C motif chemokine ligand 10 (CXCL10), interferon regulatory factor 3 (IRF3), and IRF7, while the phosphorylation of IRF3 was not detected. Moreover, the interactions between TPL2 and VP1 were also confirmed. The overexpression of TPL2 promoted IRF3-mediated dose-dependent activation of the IFN-ß signaling pathway in association with interactions between IRF3 and TPL2. VP1 also inhibited phosphorylation of TPL2 at Thr290, while Thr290 resulted as the key functional site associated with the TPL2-mediated antiviral response. Taken together, this study indicated that FMDV capsid protein VP1 antagonizes TPL2-mediated activation of the IRF3/IFN-ß signaling pathway for immune escape and facilitated virus replication.


Assuntos
Proteínas do Capsídeo/metabolismo , Vírus da Febre Aftosa/imunologia , Vírus da Febre Aftosa/fisiologia , Fator Regulador 3 de Interferon/metabolismo , Interferon beta/metabolismo , Animais , Artiodáctilos , Proteínas do Capsídeo/imunologia , Febre Aftosa , Interações Hospedeiro-Patógeno , Humanos , Evasão da Resposta Imune , MAP Quinase Quinase Quinases/metabolismo , Camundongos , Proteínas Proto-Oncogênicas/metabolismo , Transdução de Sinais , Suínos , Replicação Viral
11.
Oncol Lett ; 18(3): 2891-2896, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31452769

RESUMO

Matrine has been demonstrated to exert anticancer effects on acute myeloid leukemia (AML) cell lines. However, the mechanisms of matrine in AML remain largely unknown. The present study investigated the anticancer effects and underlying mechanisms of matrine on human AML cells in vitro. THP-1 cell lines were cultured and treated with different doses of matrine (0.4, 0.8, 1.2, 1.6 and 2.0 g/l). The effects of matrine on the cell proliferation were assessed by the Cell Counting Kit-8 assay. The apoptotic effects were evaluated by DAPI and annexin V/propidium iodide staining assays. The effects of the drug on phosphoinositide 3-kinase (PI3K)/protein kinase B (Akt)/ mechanistic target of rapamycin kinase (mTOR) protein expression were studied by western blot analysis. The results of the present study demonstrated that matrine suppressed the viability of THP-1 cells. The anticancer effects were identified to be dose-dependent and the IC50 value was 1.2 g/l in THP-1 cells. Matrine inhibited cell viability and induced cell apoptosis of AML cell lines in a dose- and time-dependent manner. In addition, it was observed that matrine decreased the expression of phosphorylated (p)-PI3K, p-Akt and p-mTOR in a concentration-dependent manner. However, the expression levels of PI3K, Akt and mTOR remained almost unaltered. These findings indicated that matrine may inhibit cell proliferation and induce apoptosis of AML cells and may be a novel effective chemotherapeutic agent against AML.

12.
J Environ Sci (China) ; 82: 155-168, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31133261

RESUMO

To understand the physical and chemical characteristics, particle size distribution and sources of size-separated aerosols in Lhasa, which is located on the Tibetan Plateau (TP), six sizes of aerosol samples were collected in Lhasa in 2014. Ca2+, NH4+, NO3-, SO42- and Cl- were the dominant ions. The ratio of cation equivalents (CE) to anion equivalents (AE) for each particle size segment indicated that the atmospheric aerosols in Lhasa were alkaline. SO42- and NO3- could be neutralized by Ca2+, but could not be neutralized by NH4+, according to the [NH4+]/[NO3- + SO42-] and [Ca2+]/[NO3- + SO42-] ratios. Mobile sources were dominant in PM0.95-1.5, PM1.5-3 and PM3-7.2, while stationary sources were dominant in the other three size fractions according to the [NO3-]/[SO42-] ratios. The particle size distribution of all water-soluble ions during monsoon and non-monsoon periods was characterized by a bimodal distribution due to the different sources and formation mechanisms, and it was revealed that different ions had different sources in different seasons and different particle size segments by combining particle size distribution with correlation analysis. Source analysis of aerosols in Lhasa was performed using the Principal component analysis (PCA) for the first time, which revealed that combustion sources, motor vehicle exhaust, photochemical reaction sources and various types of dust were the main sources of Lhasa aerosols. Furthermore, Lhasa's air quality was also affected by long-distance transmission, expressed as pollutants from South Asia and West Asia, which were transmitted to Lhasa according to backward trajectory analysis.


Assuntos
Poluentes Atmosféricos/análise , Monitoramento Ambiental , Chuva/química , Aerossóis/análise , Material Particulado/análise , Estações do Ano , Solubilidade , Tibet
13.
Langmuir ; 35(14): 4806-4812, 2019 04 09.
Artigo em Inglês | MEDLINE | ID: mdl-30865827

RESUMO

The continuous development of semiconductor quantum dots (QDs) in biochemical research has attracted special attention, and surface functionalizing becomes more important to optimize their performance. Ligand exchange reactions are commonly used to modify the surface of QDs for their biomedical applications. However, the kinetics of ligand exchange for semiconductor QDs remain fully unexplored. Here, we describe a simple and rapid method to characterize the ligand exchange reactions on CdSe/ZnS QDs by capillary electrophoresis (CE). The results of ultraviolet-visible absorption spectra, fluorescence spectra, and Fourier transform infrared spectroscopy indicated the successful implementation of the ligand exchange process. The dynamics of ligand exchange of OA-coated CdSe/ZnS QDs with 4-mercaptobenzoic acid was monitored by CE, and the observed ligand exchange trends were fitted with logistic functions. When the ligand exchange reactions reached equilibrium, the ligand density of QDs can be quantified by CE. It is anticipated that CE will be a new powerful technique for quantitative analysis of the ligand exchange reactions on the surface of QDs.

14.
J Chromatogr A ; 1578: 91-98, 2018 Nov 30.
Artigo em Inglês | MEDLINE | ID: mdl-30327181

RESUMO

Levodopa (L-DOPA) is promising as chiral stationary phase for open tubular capillary electrochromatography (OT-CEC) enantioseparation owing to its self-polymerization adhesive property and chiral recognition potential. In this work, CuSO4/H2O2 was used as a trigger agent to accelerate the polymerization process of L-DOPA and the poly-levodopa (poly-(L-DOPA)) coated column was successfully prepared for the first time by depositing it on the inner wall of fused silica capillary via the rapid and in-situ approach at room temperature. The performance of the poly-(L-DOPA) coated capillary was validated by the separation of different chiral analytes, including chiral amine drugs, neurotransmitters and amino acids, and the good enantioseparation efficiencies were achieved. For five consecutive runs, the relative standard deviations (RSDs) for the migration time of the analytes for intra-day, inter-day and column-to-column were in the range of 0.19-1.33%, 0.96-4.47%, and 2.21-7.79%, respectively. Additionally, the poly-(L-DOPA) coated capillary column could be successively used over 250 runs without observable change in the separation efficiency.


Assuntos
Eletrocromatografia Capilar/instrumentação , Técnicas de Química Analítica/instrumentação , Técnicas de Química Analítica/métodos , Levodopa/química , Sulfato de Cobre/química , Peróxido de Hidrogênio/química , Dióxido de Silício/química , Estereoisomerismo
15.
Chem Commun (Camb) ; 54(88): 12515-12518, 2018 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-30345435

RESUMO

An octanuclear Cu(ii) cluster [Cu8(dpk·OH)8(OAc)4](ClO4)4 (dpk·OH = the monoanion of the hydrated, gem-diol form of di-2-pyridyl ketone) that contains two Cu4O4 cubic fragments similar to the Mn4CaO5 cluster in photosystem II (PSII) was found to be an efficient catalyst for photocatalytic water oxidation. In the [Ru(bpy)3]2+/Na2S2O8 system, it afforded an optimal oxygen yield, turnover number (TON) and turnover frequency (TOF) of 35.6%, 178 and 3.6 s-1, respectively, which are the highest values amongst all of the Cu-based photocatalytic water oxidation catalysts (WOCs).

16.
Thorac Cancer ; 9(10): 1215-1219, 2018 10.
Artigo em Inglês | MEDLINE | ID: mdl-30070063

RESUMO

BACKGROUND: The aim of this study was to evaluate the clinical factors relevant to the prognosis of patients with esophageal cancer who received intensity-modulated radiotherapy (IMRT). METHODS: The data of 60 patients admitted to our hospital from January 2014 to December 2015 with pathologically confirmed esophageal cancer were retrospectively reviewed. All patients received IMRT. Patients were divided into groups according to two-year survival: those who survived > 2 years after treatment, and those who died within 2 years of treatment. The potential clinical factors relevant to prognosis were evaluated by logistic regression analysis. RESULTS: Single factor analysis showed that lesion length (P < 0.05), tumor diameter (P < 0.05), T stage (P < 0.05), N stage (P < 0.05), and combined chemotherapy (P < 0.05) were associated with the prognosis of esophageal cancer patients who received IMRT. Logistic regression analysis demonstrated that T stage (odds ratio = 3.62; P < 0.05) and N stage (odds ratio = 2.98; P < 0.05) were independent factors relevant to prognosis. CONCLUSION: T stage and N stage influence the long-term curative effects of IMRT for esophageal cancer. The higher the stage, the lower the two-year survival rate.


Assuntos
Neoplasias Esofágicas/radioterapia , Radioterapia de Intensidade Modulada/métodos , Neoplasias Esofágicas/patologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Prognóstico
17.
Pediatr Surg Int ; 34(4): 399-404, 2018 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-29468407

RESUMO

OBJECTIVE: To assess the efficacy of intravenous immunoglobulin (IVIG) as add-on treatment for intractable cholangitis (IC) after Kasai portoenterostomy (KPE) in biliary atresia (BA) patients. METHODS: 113 BA patients who had one or more episodes of cholangitis after KPE were recruited in this study. According to whether response to routine conservative treatment, all patients were divided into IC group and simple cholangitis (SC) group. Meanwhile, patients with IC subdivided into IVIG group and control group according to whether application of IVIG. RESULTS: The IC group had higher serum procalcitonin (PCT) (P = 0.014), C-reactive protein (CRP) (P = 0.023), and γ-Gltamyltranspeptidase (γ-GGT) (P = 0.031) level than the SC group. The IVIG group had shorter duration of fever after treatment (P = 0.011) and length of hospital stay (P = 0.018) than the control group. The time until recurrent episode of cholangitis was significant longer in IVIG group than in control group (P = 0.019). CONCLUSIONS: IVIG as add-on treatment may be an effective treatment for the cholangitis acute episode, and we conclude by calling for more prospective studies to attest to the role of IVIG in the treatment of cholangitis.


Assuntos
Atresia Biliar/cirurgia , Colangite/tratamento farmacológico , Imunoglobulinas Intravenosas/administração & dosagem , Portoenterostomia Hepática/efeitos adversos , Complicações Pós-Operatórias/tratamento farmacológico , Colangite/etiologia , Feminino , Humanos , Fatores Imunológicos/administração & dosagem , Lactente , Recém-Nascido , Masculino , Complicações Pós-Operatórias/etiologia , Estudos Prospectivos , Fatores de Tempo , Resultado do Tratamento
18.
Oxid Med Cell Longev ; 2015: 352723, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26171115

RESUMO

Alzheimer's disease (AD) is the most common form of dementia. The pathological hallmarks of AD are amyloid plaques [aggregates of amyloid-beta (Aß)] and neurofibrillary tangles (aggregates of tau). Growing evidence suggests that tau accumulation is pathologically more relevant to the development of neurodegeneration and cognitive decline in AD patients than Aß plaques. Oxidative stress is a prominent early event in the pathogenesis of AD and is therefore believed to contribute to tau hyperphosphorylation. Several studies have shown that the autophagic pathway in neurons is important under physiological and pathological conditions. Therefore, this pathway plays a crucial role for the degradation of endogenous soluble tau. However, the relationship between oxidative stress, tau protein hyperphosphorylation, autophagy dysregulation, and neuronal cell death in AD remains unclear. Here, we review the latest progress in AD, with a special emphasis on oxidative stress, tau hyperphosphorylation, and autophagy. We also discuss the relationship of these three factors in AD.


Assuntos
Doença de Alzheimer/patologia , Autofagia , Estresse Oxidativo , Proteínas tau/metabolismo , Doença de Alzheimer/metabolismo , Antioxidantes/metabolismo , Humanos , Fosforilação , Espécies Reativas de Oxigênio/metabolismo
19.
Huan Jing Ke Xue ; 33(4): 1041-9, 2012 Apr.
Artigo em Chinês | MEDLINE | ID: mdl-22720544

RESUMO

To effectively reduce urban carbon emissions and verify the effectiveness of currently project for urban carbon emission reduction, quantitative estimation sources of urban atmospheric CO2 correctly is necessary. Since little fractionation of carbon isotope exists in the transportation from pollution sources to the receptor, the carbon isotope composition can be used for source apportionment. In the present study, a method was established to quantitatively estimate the source of urban atmospheric CO2 by the carbon isotope composition. Both diurnal and height variations of concentrations of CO2 derived from biomass, vehicle exhaust and coal burning were further determined for atmospheric CO2 in Jiading district of Shanghai. Biomass-derived CO2 accounts for the largest portion of atmospheric CO2. The concentrations of CO2 derived from the coal burning are larger in the night-time (00:00, 04:00 and 20:00) than in the daytime (08:00, 12:00 and 16:00), and increase with the increase of height. Those derived from the vehicle exhaust decrease with the height increase. The diurnal and height variations of sources reflect the emission and transport characteristics of atmospheric CO2 in Jiading district of Shanghai.


Assuntos
Poluentes Atmosféricos/análise , Atmosfera/análise , Dióxido de Carbono/análise , Isótopos de Carbono/análise , Emissões de Veículos/análise , China , Cidades , Carvão Mineral/análise , Monitoramento Ambiental/métodos
20.
Biosens Bioelectron ; 26(8): 3602-7, 2011 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-21388799

RESUMO

The three-dimensionally ordered macroporous gold-nanoparticle-doped titanium dioxide (3DOM GTD) film was modified on the indium-tin oxide (ITO) electrode surface. Hemoglobin (Hb) has been successfully immobilized on the 3DOM GTD film and the fabrication process was characterized by Raman and UV-vis spectra. The results indicated that the Hb immobilized on the film retained its biological activity and the secondary structure of Hb was not destroyed. The direct electrochemistry and electrocatalysis of Hb immobilized on this film have been investigated. The Hb/3DOM GTD/ITO electrode exhibited two couples of redox peaks corresponding to the Hb intercalated in the mesopores and adsorbed on the external surface of the film with the formal potential of -0.20 and -0.48 V in 0.1M PBS (pH7.0), respectively. The Hb/3DOM GTD/ITO electrode exhibits an excellent eletrocatalytic activity, a wide linear range for H(2)O(2) from 5.0 µM to 1.0mM with a limit of detection of 0.6µM, high sensitivity (144.5 µA mM(-1)), good stability and reproducibility. Compared with the TiO(2) nanoneedles modified electrode, the GTD modified electrode has higher sensitivity and response peak current. The 3DOM GTD provided a good matrix for bioactive molecules immobilization, suggesting it has the potential use in the fields of H(2)O(2) biosensors.


Assuntos
Técnicas Biossensoriais/métodos , Técnicas Eletroquímicas/métodos , Hemoglobinas/química , Peróxido de Hidrogênio/análise , Eletrodos , Ouro/química , Nanopartículas Metálicas/química , Reprodutibilidade dos Testes , Titânio/química
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