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1.
Nano Lett ; 24(22): 6821-6827, 2024 Jun 05.
Artigo em Inglês | MEDLINE | ID: mdl-38787786

RESUMO

In the quasi-two-dimensional superconductor NbSe2, the superconducting transition temperature (Tc) is layer-dependent, decreasing by about 60% in the monolayer limit. However, for the extremely anisotropic copper-based high-Tc superconductor Bi2Sr2CaCu2O8+δ (Bi-2212), the Tc of the monolayer is almost identical with that of its bulk counterpart. To clarify the effect of dimensionality on superconductivity, here, we successfully fabricate ultrathin flakes of iron-based high-Tc superconductors CsCa2Fe4As4F2 and CaKFe4As4. It is found that the Tc of monolayer CsCa2Fe4As4F2 (after tuning to the optimal doping by ionic liquid gating) is about 20% lower than that of the bulk crystal, while the Tc of three-layer CaKFe4As4 decreases by 46%, showing a more pronounced dimensional effect than that of CsCa2Fe4As4F2. By carefully examining their anisotropy and the c-axis coherence length, we reveal the general trend and empirical law of the layer-dependent superconductivity in these quasi-two-dimensional superconductors.

2.
Support Care Cancer ; 32(1): 16, 2023 Dec 12.
Artigo em Inglês | MEDLINE | ID: mdl-38085376

RESUMO

PURPOSE: The opioid crisis resulting from its use disorder and overdose poses additional challenges for cancer pain management. The American Society of Clinical Oncology Practice Guideline recommends acupuncture therapy for the management of adult cancer-related pain (CRP), but the effectiveness of transcutaneous electrical acupoint stimulation (TEAS) on CRP remains uncertain. METHODS: This 5-week prospective randomized clinical trial was conducted at 2 hospitals in China, and participants with CRP receiving chronic opioid therapy were randomized 1:1 into two groups between December 2014 and June 2018. The true TEAS group underwent 15 sessions of TEAS treatments over 3 consecutive weeks, while the control group received sham stimulation. The primary outcome was the numerical rating scale (NRS) score in the past 24h at week 3. The secondary outcomes included morphine equivalent daily dose, quality of life and adverse events. RESULTS: A total of 159 participants were included in the modified intention-to-treat population. The baseline characteristics were similar in both groups. The mean NRS scores were 0.98 points at week 3 in the true TEAS group and 1.41 points in the sham group, with the mean difference between groups of -0.43 points (P < 0.001; OR = 0.68, P < 0.05). The proportion of patients with NRS reduction more than thirty percentage at week 3 was 50.00% in the true TEAS group and 35.44% in the sham group (RD = 0.15, P > 0.05; RR = 1.41, P > 0.05). No significant difference in pain intensity between the two groups was observed during the follow-up period without TEAS intervention (week 4, OR = 0.83, P > 0.05; week 5, OR = 0.83, P > 0.05). The Karnofsky Performance Status value suggested that patients in the true TEAS group experienced an improved quality of life (Between-group differences: week 3, 3.5%, P < 0.05; week 4, 4.6%, P < 0.001; week 5, 5.6%, P < 0.001). CONCLUSIONS: The 3-week application of TEAS in patients with CRP receiving chronic opioid therapy resulted in a statistically significant reduction in pain scores, but the observed reduction was of uncertain clinical significance. The prolonged analgesic effect of TEAS was not confirmed in this trial. CLINICALTRIAL: GOV: ChiCTR-TRC-13003803.


Assuntos
Dor do Câncer , Neoplasias , Estimulação Elétrica Nervosa Transcutânea , Adulto , Humanos , Pontos de Acupuntura , Analgésicos Opioides/efeitos adversos , Dor do Câncer/tratamento farmacológico , Dor do Câncer/etiologia , Morfina , Neoplasias/terapia , Neoplasias/tratamento farmacológico , Manejo da Dor , Estudos Prospectivos , Qualidade de Vida , Estimulação Elétrica Nervosa Transcutânea/métodos
3.
Mol Cell ; 31(1): 124-33, 2008 Jul 11.
Artigo em Inglês | MEDLINE | ID: mdl-18614051

RESUMO

Activation of heterodimeric (alpha/beta) integrin transmembrane receptors by the 270 kDa cytoskeletal protein talin is essential for many important cell adhesive and physiological responses. A key step in this process involves interaction of phosphotyrosine-binding (PTB) domain in the N-terminal head of talin (talin-H) with integrin beta membrane-proximal cytoplasmic tails (beta-MP-CTs). Compared to talin-H, intact talin exhibits low potency in inducing integrin activation. Using NMR spectroscopy, we show that the large C-terminal rod domain of talin (talin-R) interacts with talin-H and allosterically restrains talin in a closed conformation. We further demonstrate that talin-R specifically masks a region in talin-PTB where integrin beta-MP-CT binds and competes with it for binding to talin-PTB. The inhibitory interaction is disrupted by a constitutively activating mutation (M319A) or by phosphatidylinositol 4,5-bisphosphate, a known talin activator. These data define a distinct autoinhibition mechanism for talin and suggest how it controls integrin activation and cell adhesion.


Assuntos
Cadeias beta de Integrinas/metabolismo , Talina/antagonistas & inibidores , Talina/química , Animais , Sítios de Ligação , Células CHO , Membrana Celular/efeitos dos fármacos , Membrana Celular/metabolismo , Cricetinae , Cricetulus , Cadeias beta de Integrinas/química , Espectroscopia de Ressonância Magnética , Camundongos , Modelos Biológicos , Modelos Moleculares , Fosfatidilinositol 4,5-Difosfato/farmacologia , Ligação Proteica/efeitos dos fármacos , Estrutura Terciária de Proteína , Relação Estrutura-Atividade
4.
Clin Lab ; 61(7): 731-9, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26299072

RESUMO

BACKGROUND: CD20 positive NK/T-cell lymphoma is extremely rare and difficult for clinical treatment. Due to the lack of an established cell model for this disease, less is known about its biological characterization and potential therapeutic options. METHODS: A cell line of NK/T-cell lymphoma, which was enriched by magnetic sorting with proper cell surface markers (CD56) from peripheral blood mononuclear cells (PBMCs) drawn from a 21-year-old male patient with nasal angiocentric NK/T-cell lymphoma, was designated as ZQNK-29. Immunophenotypic analysis of ZQNK-29 was performed by flow cytometric and immunohistochemical analysis. Comparative genomic hybridization (CGH) analysis was used for cytogenetic analysis of ZQNK-29. Potential rearrangements of the immunoglobulin gene and Epstein-Barr virus (EBV) infection were examined by PCR and RT-PCR, respectively. RESULTS: ZQNK-29 cells express the phenotypic T-cell marker (CD3), T cell activation markers (HLA-DR), markers for both NK and cytotoxic T lymphocytes (TIA-1), and B-lineage marker CD20; however, expression of CD56 was not detected in expanded ZQNK-29 cells although this NK cell surface marker was used as one of selective cell surface markers for the initial isolation of NK/T cells. RT-PCR analysis showed that the pattern of gene expressions for infected EBV was latency type III, with the expressions of LMP1, EBNA-1, and EBNA-2; no rearrangements were found in the heavy-chain of the immunoglobulin gene or in the y chain of the T cell receptors (TCRs) gene. CGH analysis demonstrated that ZQNK-29 possessed an abnormal karyotype, 46XY, 1p (dist)+, 4p (dist)+, 4q (mid)-, 5q (mid)-, 9q (dist)+, 16p (dist)+, 16q (dist)+, 17p+, 17q (dist)+, 19q (dist)+, 20p+, 20q+, 21q+, and 22q+. Of these, 1p (dist)+, which has been confirmed to be mitochondrial DNA amplification, is believed to be mainly caused by EBV infection. CONCLUSIONS: ZQNK-29 is a well characterized premature human NK/T-cell lymphoma cell line with expression of the B-cell marker CD20 and will provide a useful pre-clinic model for characterization and potential therapeutic studies of the aggressive NK/T-cell lymphoma.


Assuntos
Antígenos CD20/metabolismo , Biomarcadores Tumorais/metabolismo , Separação Imunomagnética , Linfoma Extranodal de Células T-NK/metabolismo , Neoplasias Nasais/metabolismo , Biomarcadores Tumorais/genética , Linhagem Celular Tumoral , Forma Celular , Aberrações Cromossômicas , Hibridização Genômica Comparativa , Citometria de Fluxo , Rearranjo Gênico , Rearranjo Gênico da Cadeia gama dos Receptores de Antígenos dos Linfócitos T , Genes de Cadeia Pesada de Imunoglobulina , Genes Codificadores da Cadeia gama de Receptores de Linfócitos T , Predisposição Genética para Doença , Herpesvirus Humano 4/genética , Humanos , Imuno-Histoquímica , Imunofenotipagem/métodos , Cariotipagem , Linfoma Extranodal de Células T-NK/genética , Linfoma Extranodal de Células T-NK/imunologia , Linfoma Extranodal de Células T-NK/patologia , Linfoma Extranodal de Células T-NK/virologia , Masculino , Neoplasias Nasais/genética , Neoplasias Nasais/imunologia , Neoplasias Nasais/patologia , Neoplasias Nasais/virologia , Fenótipo , Reação em Cadeia da Polimerase em Tempo Real , Adulto Jovem
5.
Int J Med Sci ; 11(7): 685-90, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-24843317

RESUMO

OBJECTIVES: Low-density lipoprotein receptor-related protein 6 (LRP6) modulates Wnt signaling transduction. Altered LRP6 expression leads to abnormal Wnt protein activation, cell proliferation and tumorigenesis. This study investigated the association between LRP6 single-nucleotide polymorphisms (SNPs) and non-small-cell lung cancer (NSCLC) in a Chinese population. METHODS: A total of 500 NSCLC patients and 500 healthy controls were recruited for assessment of four LRP6 SNPs using the SEQUENOM MassARRAY matrix-assisted laser desorption ionization-time of flight mass spectrometry. The association between genotype and NSCLC risk was evaluated by computing the odds ratio (OR) and 95% confidence interval (CI) with multivariate unconditional logistic regression analyses. RESULTS: The frequency of the LRP6 rs10845498 genotype was 60.9% (A/A), 35.5% (AG) and 3.6% (GG) in patients with lung squamous cell carcinoma (SCC) and 69.2% (A/A), 27.2% (A/G) and 3.6% (GG) in controls. Logistic regression analysis revealed that the LRP6 rs10845498 A/A major allele was associated with a reduced risk in developing lung SCC (OR = 0.69; 95% CI, 0.48-1.00; P=0.04), and tobacco smokers had a 2.21 fold greater risk in developing SCC than nonsmokers (p<0.01, 95% CI, 1.72-2.85), and tobacco smokers who carried an "A" allele (AA+AG) in rs6488507 had a 2.34-fold greater risk in developing NSCLC than other patients (p< 0.01, 95%CI, 1.74-3.13). CONCLUSIONS: The LRP6 rs10845498 SNP is associated with a reduced risk of lung SCC, while tobacco smoke increases the risk. LRP6 rs6488507 polymorphism synergistically increased the risk of NSCLC in tobacco smokers. Further studies are needed to elucidate the functional impact of LRP6 expression and activity in NSCLC.


Assuntos
Carcinoma Pulmonar de Células não Pequenas/genética , Estudos de Associação Genética , Predisposição Genética para Doença , Proteína-6 Relacionada a Receptor de Lipoproteína de Baixa Densidade/genética , Povo Asiático , Carcinoma Pulmonar de Células não Pequenas/patologia , Feminino , Frequência do Gene , Genótipo , Humanos , Masculino , Polimorfismo de Nucleotídeo Único , Fatores de Risco , Fumar/efeitos adversos
6.
Front Microbiol ; 15: 1410368, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38873146

RESUMO

Ganoderic acids (GAs) are major functional components of Ganoderma lucidum. The study aimed to breed a new G. lucidum strain with increased contents of individual GAs. Two mating-compatible monokaryotic strains, G. 260125 and G. 260124, were successfully isolated from the dikaryotic G. lucidum CGMCC 5.0026 via protoplast formation and regeneration. The Vitreoscilla hemoglobin gene (vgb) and squalene synthase gene (sqs) were overexpressed in the monokaryotic G. 260124 and G. 260125 strain, respectively. Mating between the G. 260124 strain overexpressing vgb and the G. 260125 strain overexpressing sqs resulted in the formation of the new hybrid dikaryotic G. lucidum strain sqs-vgb. The maximum contents of ganoderic acid (GA)-T, GA-Me, and GA-P in the fruiting body of the mated sqs-vgb strain were 23.1, 15.3, and 39.8 µg/g dry weight (DW), respectively, 2.23-, 1.75-, and 2.69-fold greater than those in G. lucidum 5.0026. The squalene and lanosterol contents increased 2.35- and 1.75-fold, respectively, in the fruiting body of the mated sqs-vgb strain compared with those in the G. lucidum 5.0026. In addition, the maximum expression levels of the sqs and lanosterol synthase gene (ls) were increased 3.23- and 2.13-fold, respectively, in the mated sqs-vgb strain. In summary, we developed a new G. lucidum strain with higher contents of individual GAs in the fruiting body by integrating genetic engineering and mono-mono crossing.

7.
Eur J Pharmacol ; 946: 175548, 2023 May 05.
Artigo em Inglês | MEDLINE | ID: mdl-36706801

RESUMO

Aging is a process accompanied by widespread degenerative changes which are a major cause of human disease and disability. One goal of aging research is to develop interventions or drugs that can extend organism lifespan and treat age-related diseases. Here, we report the identification of a broad spectrum anti-viral agent, ribavirin, as a potential pharmacological aging intervention. Ribavirin extended the lifespan and healthspan of Caenorhabditis elegans by inhibiting Target of Rapamycin (TOR) signaling and activating AMP-activated protein kinase (AMPK). Moreover, our data indicate that ribavirin activated AMPK by reducing the levels of adenosine triphosphate (ATP) and lysosomal v-ATPase-Ragulator-AXIN Complex. Thus, our studies successfully identify ribavirin as a potential anti-aging drug, and indicate that its anti-aging effect is mediated via AMPK-TOR signaling.


Assuntos
Caenorhabditis elegans , Longevidade , Animais , Humanos , Proteínas Quinases Ativadas por AMP/metabolismo , Ribavirina/farmacologia , Transdução de Sinais
8.
Hortic Res ; 10(6): uhad073, 2023 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-37303613

RESUMO

An ancient hexaploidization event in the most but not all Asteraceae plants, may have been responsible for shaping the genomes of many horticultural, ornamental, and medicinal plants that promoting the prosperity of the largest angiosperm family on the earth. However, the duplication process of this hexaploidy, as well as the genomic and phenotypic diversity of extant Asteraceae plants caused by paleogenome reorganization, are still poorly understood. We analyzed 11 genomes from 10 genera in Asteraceae, and redated the Asteraceae common hexaploidization (ACH) event ~70.7-78.6 million years ago (Mya) and the Asteroideae specific tetraploidization (AST) event ~41.6-46.2 Mya. Moreover, we identified the genomic homologies generated from the ACH, AST and speciation events, and constructed a multiple genome alignment framework for Asteraceae. Subsequently, we revealed biased fractionations between the paleopolyploidization produced subgenomes, suggesting the ACH and AST both are allopolyplodization events. Interestingly, the paleochromosome reshuffling traces provided clear evidence for the two-step duplications of ACH event in Asteraceae. Furthermore, we reconstructed ancestral Asteraceae karyotype (AAK) that has 9 paleochromosomes, and revealed a highly flexible reshuffling of Asteraceae paleogenome. Of specific significance, we explored the genetic diversity of Heat Shock Transcription Factors (Hsfs) associated with recursive whole-genome polyploidizations, gene duplications, and paleogenome reshuffling, and revealed that the expansion of Hsfs gene families enable heat shock plasticity during the genome evolution of Asteraceae. Our study provides insights on polyploidy and paleogenome remodeling for the successful establishment of Asteraceae, and is helpful for further communication and exploration of the diversification of plant families and phenotypes.

9.
Drug Deliv ; 29(1): 1595-1607, 2022 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-35612309

RESUMO

At present, the 10-year survival rate of patients with pancreatic cancer is still less than 4%, mainly due to the high cancer recurrence rate caused by incomplete surgery and lack of effective postoperative adjuvant treatment. Systemic chemotherapy remains the only choice for patients after surgery; however, it is accompanied by off-target effects and server systemic toxicity. Herein, we proposed a biodegradable microdevice for local sustained drug delivery and postoperative pancreatic cancer treatment as an alternative and safe option. Biodegradable poly(l-lactic-co-glycolic acid) (P(L)LGA) was developed as the matrix material, gemcitabine hydrochloride (GEM·HCl) was chosen as the therapeutic drug and polyethylene glycol (PEG) was employed as the drug release-controlled regulator. Through adjusting the amount and molecular weight of PEG, the controllable degradation of matrix and the sustained release of GEM·HCl were obtained, thus overcoming the unstable drug release properties of traditional microdevices. The drug release mechanism of microdevice and the regulating action of PEG were studied in detail. More importantly, in the treatment of the postoperative recurrence model of subcutaneous pancreatic tumor in mice, the microdevice showed effective inhibition of postoperative in situ recurrences of pancreatic tumors with excellent biosafety and minimum systemic toxicity. The microdevice developed in this study provides an option for postoperative adjuvant pancreatic treatment, and greatly broadens the application prospects of traditional chemotherapy drugs.


Assuntos
Recidiva Local de Neoplasia , Neoplasias Pancreáticas , Animais , Linhagem Celular Tumoral , Desoxicitidina/análogos & derivados , Sistemas de Liberação de Medicamentos , Humanos , Ácido Láctico , Camundongos , Recidiva Local de Neoplasia/tratamento farmacológico , Neoplasias Pancreáticas/tratamento farmacológico , Polietilenoglicóis/uso terapêutico , Gencitabina , Neoplasias Pancreáticas
10.
ACS Omega ; 6(11): 7499-7511, 2021 Mar 23.
Artigo em Inglês | MEDLINE | ID: mdl-33778262

RESUMO

The interactions between latex and cement are still not completely understood. In this work, we would like to address the temporal changes in cement hardening and latex film formation. For this reason, the hydration process and the film formation were simultaneously monitored. This scientific issue is even more challenging as a nondestructive quantitative analysis of the film formation process is not available yet. Here, we report on simultaneous monitoring of the latex film formation and the phase development in cementitious systems via 1H-time-domain-NMR for the first time. The obtained results were validated using classical analytical methods, such as in situ X-ray diffraction, X-ray fluorescence (Rietveld analysis), and confocal laser scanning microscopy.

11.
Nucleic Acids Res ; 36(9): 3128-38, 2008 May.
Artigo em Inglês | MEDLINE | ID: mdl-18411209

RESUMO

Drosophila melanogaster MTF-1 (dMTF-1) is a copper-responsive transcriptional activator that mediates resistance to Cu, as well as Zn and Cd. Here, we characterize a novel cysteine-rich domain which is crucial for sensing excess intracellular copper by dMTF-1. Transgenic flies expressing mutant dMTF-1 containing alanine substitutions of two, four or six cysteine residues within the sequence (547)CNCTNCKCDQTKSCHGGDC(565) are significantly or completely impaired in their ability to protect flies from copper toxicity and fail to up-regulate MtnA (metallothionein) expression in response to excess Cu. In contrast, these flies exhibit wild-type survival in response to copper deprivation thus revealing that the cysteine cluster domain is required only for sensing Cu load by dMTF-1. Parallel studies show that the isolated cysteine cluster domain is required to protect a copper-sensitive S. cerevisiae ace1Delta strain from copper toxicity. Cu(I) ligation by a Cys-rich domain peptide fragment drives the cooperative assembly of a polydentate [Cu(4)-S(6)] cage structure, characterized by a core of trigonally S(3) coordinated Cu(I) ions bound by bridging thiolate ligands. While reminiscent of Cu(4)-L(6) (L = ligand) tetranuclear clusters in copper regulatory transcription factors of yeast, the absence of significant sequence homology is consistent with convergent evolution of a sensing strategy particularly well suited for Cu(I).


Assuntos
Cobre/toxicidade , Cisteína/química , Proteínas de Ligação a DNA/química , Drosophila melanogaster/metabolismo , Fatores de Transcrição/química , Sequência de Aminoácidos , Animais , Animais Geneticamente Modificados , Cobre/química , Proteínas de Ligação a DNA/genética , Proteínas de Ligação a DNA/metabolismo , Drosophila melanogaster/efeitos dos fármacos , Drosophila melanogaster/genética , Dados de Sequência Molecular , Mutação , Ligação Proteica , Estrutura Terciária de Proteína , Saccharomyces cerevisiae/efeitos dos fármacos , Análise Espectral , Enxofre/química , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Raios X , Fator MTF-1 de Transcrição
12.
Chemosphere ; 241: 125028, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31629233

RESUMO

The kinetics of elemental mercury (Hg0) release from fly ashes and hydrated fly ash cement pastes was investigated using a homemade Hg measurement system. Three types of fly ash (FA) and ordinary Portland cement (OPC) were used to prepare cement pastes. After standard curing for 28 days, the hydrated cement paste (HCP) was ground into a fine powder for Hg emission measurements. Detectable Hg0 was found released from both fly ashes and hydrated fly ash cement pastes. The results show that elevated temperatures and evaporation of the capillary pore water in wet HCP samples accelerate Hg0 release. Both desorption of Hg0 from the particle surface of HCP powder and migration of Hg0 from the inner pores contribute to Hg0 release. The kinetic calculation indicates that the hydration products of hydrated fly ash cement have little immobilization effect on Hg0, which is mainly physically encapsulated in the HCP particles by hydration products.


Assuntos
Cinza de Carvão/química , Materiais de Construção , Mercúrio/farmacocinética , Carbono , Temperatura Alta , Cinética , Água
13.
Trials ; 20(1): 40, 2019 Jan 11.
Artigo em Inglês | MEDLINE | ID: mdl-30635007

RESUMO

BACKGROUND: Transcutaneous electrical acupoint stimulation (TEAS), which is also known as acupuncture-like transcutaneous electrical nerve stimulation (TENS), has been widely used in acute or chronic pain. However, previous research has not demonstrated that TEAS is effective for cancer-related pain. Opioid drugs are strongly recommended for treating cancer-related pain, but opioid-induced immunosuppression is still the most intractable drug-induced medical problem. Evaluating the efficacy and potential advantage of TEAS combined with opioid drugs in moderate and severe cancer-related pain in China is important because such studies are lacking. METHODS/DESIGN: This trial is a multicenter, prospective randomized controlled clinical trial. In total, 160 patients who were enrolled from two hospitals in the Zhejiang Province (China) will be randomly allocated into two groups: a TEAS group and sham TEAS group without acupoint electrical stimulation. Both groups will receive a 21-day interval of chemotherapy and conventional cancer pain therapy. Fifteen treatment sessions will be performed over a three-week period. The primary outcomes will be measured by changes in the Numerical Rating Scale (NRS) scores and equivalent dosage of morphine at baseline, three weeks of treatment and one two-week follow-up. The secondary outcome measures include cellular immunity function, life quality assessment, opioids side effects assessment, and safety and compliance evaluation. DISCUSSION: This trial is expected to clarify whether TEAS is effective for cancer-related pain. These results demonstrate the advantage of TEAS combined with opioid drugs on improving immune function and decreasing opioid induced side effects. TRIAL REGISTRATION: Chinese Clinical Trial Registry, ChiCTR-13003803 . Registered on 27 August 2013.


Assuntos
Pontos de Acupuntura , Analgésicos Opioides/uso terapêutico , Dor do Câncer/terapia , Estimulação Elétrica Nervosa Transcutânea/métodos , Adolescente , Adulto , Idoso , Analgésicos Opioides/efeitos adversos , Dor do Câncer/diagnóstico , Dor do Câncer/fisiopatologia , Dor do Câncer/psicologia , China , Terapia Combinada , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Multicêntricos como Assunto , Medição da Dor , Estudos Prospectivos , Qualidade de Vida , Ensaios Clínicos Controlados Aleatórios como Assunto , Fatores de Tempo , Estimulação Elétrica Nervosa Transcutânea/efeitos adversos , Resultado do Tratamento , Adulto Jovem
14.
J Mol Biol ; 359(1): 47-54, 2006 May 26.
Artigo em Inglês | MEDLINE | ID: mdl-16616931

RESUMO

Phosphatidylinositol-4,5-bisphosphate (PIP2) is a key lipid messenger that regulates myriad diverse cellular signaling pathways. To ensure specificity in disparate cellular events, PIP2 must be localized to specific sub-cellular sites. At PIP2-regulated focal adhesion (FA) sites, such localization is in part mediated via the recruitment and activation of PIP2-producing enzyme, type Igamma phosphatidylinositol phosphate kinase (PIPKIgamma), by a phosphotyrosine binding (PTB) domain of talin. Transient phosphorylation of PIPKIgamma at Y644 regulates the interaction and efficient FA targeting of PIPKIgamma; however, the underlying structural basis remains elusive. We have determined the NMR structure of talin-1 PTB in complex with the Y644-phosphorylated PIPKIgamma fragment (WVpYSPLH). As compared to canonical PTB domains that typically recognize the NPXpY turn motif from a variety of signaling proteins, our structure displays an unusual non-NPXpY-based recognition mode for talin-1 PTB where K(357)RW in beta5 strand forms an antiparallel beta-sheet with the VpYS of PIPKIgamma. A specific electrostatic triad between K357/R358 of talin-1 PTB and the pY644 of PIPKIgamma was observed, which is consistent with the mutagenesis and isothermal calorimetry data. Combined with previous in vivo data, our results provide a framework for understanding how phosphorylation of Y644 in PIPKIgamma promotes its specific interaction with talin-1, leading to efficient local synthesis of PIP2 and dynamic regulation of integrin-mediated FA assembly.


Assuntos
Adesões Focais/metabolismo , Fosfotransferases (Aceptor do Grupo Álcool)/química , Conformação Proteica , Talina/química , Animais , Calorimetria , Adesões Focais/química , Camundongos , Modelos Moleculares , Ressonância Magnética Nuclear Biomolecular , Fragmentos de Peptídeos/química , Fragmentos de Peptídeos/metabolismo , Fosfatidilinositol 4,5-Difosfato/metabolismo , Fosfotransferases (Aceptor do Grupo Álcool)/metabolismo , Fosfotirosina/metabolismo , Talina/metabolismo
15.
Structure ; 25(10): 1506-1518.e4, 2017 10 03.
Artigo em Inglês | MEDLINE | ID: mdl-28890360

RESUMO

Nuclear receptor (NR) transcription factors bind various coreceptors, small-molecule ligands, DNA response element sequences, and transcriptional coregulator proteins to affect gene transcription. Small-molecule ligands and DNA are known to influence receptor structure, coregulator protein interaction, and function; however, little is known on the mechanism of synergy between ligand and DNA. Using quantitative biochemical, biophysical, and solution structural methods, including 13C-detected nuclear magnetic resonance and hydrogen/deuterium exchange (HDX) mass spectrometry, we show that ligand and DNA cooperatively recruit the intrinsically disordered steroid receptor coactivator-2 (SRC-2/TIF2/GRIP1/NCoA-2) receptor interaction domain to peroxisome proliferator-activated receptor gamma-retinoid X receptor alpha (PPARγ-RXRα) heterodimer and reveal the binding determinants of the complex. Our data reveal a thermodynamic mechanism by which DNA binding propagates a conformational change in PPARγ-RXRα, stabilizes the receptor ligand binding domain dimer interface, and impacts ligand potency and cooperativity in NR coactivator recruitment.


Assuntos
DNA/metabolismo , Complexos Multiproteicos/química , Coativador 2 de Receptor Nuclear/química , Coativador 2 de Receptor Nuclear/metabolismo , Sítios de Ligação , Espectroscopia de Ressonância Magnética Nuclear de Carbono-13 , Medição da Troca de Deutério , Regulação da Expressão Gênica , Humanos , Ligantes , PPAR gama/química , PPAR gama/metabolismo , Ligação Proteica , Receptor X Retinoide alfa/química , Receptor X Retinoide alfa/metabolismo
16.
Guang Pu Xue Yu Guang Pu Fen Xi ; 24(7): 806-9, 2004 Jul.
Artigo em Zh | MEDLINE | ID: mdl-15766076

RESUMO

The crystalline behaviors of PCL(poly(epsilon-caprolactone) )thin film on Si and KBr substrates have been studied in-situ using FTIR with a heat stage. In the crystalline process, due to the decrease in free volume and the increase in interaction among different molecules, the peak of C=O shifted to lower wave number and the crystalline peak of C-O-C and C-H appeared. The degree of crystallinity has been calculated through the comparison between the peaks of crystal and amorphous parts. FTIR study on the films cast from solution with different concentrations showed that the thicker the film is, the higher crystallinity it has. This may be due to the substrate effect or geometric confinement. It was also shown that under the same preparation condition, the film on KBr wafer had higher degree of crystallinity than that of film on Si wafer.

17.
Angew Chem Int Ed Engl ; 37(20): 2859-2861, 1998 Nov 02.
Artigo em Inglês | MEDLINE | ID: mdl-29711101

RESUMO

Dramatically shortened transverse relaxation times in transverse relaxation optimized spectroscopy (TROSY) result from interference between dipole-dipole interactions and the anisotropy of the chemical shift. Thus NMR spectroscopy becomes a suitable method for studying large biomolecules, with optimal performance when 1-GHz spectrometers become available. By using new phase cycles and data-processing methods, the sensitivity of the TROSY experiment was increased by a factor of √2, which is of considerable importance for applications in high-field NMR studies on large proteins.

19.
Asian Pac J Cancer Prev ; 14(9): 5171-4, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-24175795

RESUMO

BACKGROUND: This study aimed to explore potential associations between single nucleotide polymorphisms (SNPs) of the x-ray repair cross-complementing group 1 (XRCC1) and cleft lip and palate transmembrane protein 1-like (CLPTM1L) and non-small cell lung cancer (NSCLC) susceptibility in non-smoker Chinese patients. METHODS: A total of 200 NSCLC patients and 200 healthy controls with matched age and gender were recruited for genotyping of XRCC1 SNPs (rs2256507 and rs1001581) and CLPTM1L SNPs (rs401681 and rs4975616). Association of these SNPs with NSCLC risk was evaluated by computing the odds ratio (OR) and 95% confidence interval (CI) from multivariate unconditional logistic regression analyses with adjustment for gender and age. RESULTS: The frequencies of genotype and allele in these four loci (rs2256507, rs1001581, rs401681, and rs4975616) were not significantly different between the cases and controls, or between either of the histological subgroups (adenocarcinoma and squamous cell carcinoma) and controls. CONCLUSIONS: Although these SNPs are associated with NSCLC risk in patients with a tobacco-smoking habit, this study demonstrated that XRCC1 and CLPTM1L gene SPNs are not linked with NSCLC risk in non-smoking patients, indicating that molecular mechanisms of NSCLC betwee tobacco smokers and non-smokers may be different. Future studies are needed to uncover the underlying molecular mechanisms for NSCLC in non-smokers.


Assuntos
Adenocarcinoma/genética , Povo Asiático/genética , Carcinoma Pulmonar de Células não Pequenas/genética , Carcinoma de Células Escamosas/genética , Proteínas de Ligação a DNA/genética , Neoplasias Pulmonares/genética , Proteínas de Membrana/genética , Proteínas de Neoplasias/genética , Fumar , Adulto , Idoso , Idoso de 80 Anos ou mais , Estudos de Casos e Controles , China , Feminino , Interação Gene-Ambiente , Predisposição Genética para Doença , Humanos , Masculino , Pessoa de Meia-Idade , Razão de Chances , Polimorfismo de Nucleotídeo Único , Proteína 1 Complementadora Cruzada de Reparo de Raio-X
20.
Clin Lung Cancer ; 14(1): 45-9, 2013 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-22658813

RESUMO

BACKGROUND: Recently, polymorphisms in COMT (catechol-O-methyltransferase), PLCH1 (phosphoinositide-specific phospholipase C eta 1), and CYP17A1 (cytochrome P450 17A1) were found to be associated with the development of lung cancer in a non-Chinese population. AIMS: To explore the potential association between single-nucleotide polymorphism (SNP) in COMT, PLCH1, CYP17A1, and non-small-cell lung cancer (NSCLC) susceptibility in Chinese patients who were nonsmokers. METHODS: A case-controlled study was conducted in 200 patients with NSCLC and 200 healthy controls who were age and sex matched. SNPs rs4680, rs181696, and rs743572 from the COMT, PLCH1, and CYP17A1 genes, respectively, were selected for genotyping. The association between genotype and lung cancer risk was evaluated by computing the odds ratio and 95% confidence interval from multivariate unconditional logistic regression analyses with adjustment for sex and age. RESULTS: The frequency of the G genotype in COMT rs4680 was statistically different between patients with NSCLC and controls (P = .04), and between patients with adenocarcinomas (ADC) and controls (P = .02). The frequency of the A genotype in PLCH1 rs181696 occurred more frequently in squamous cell carcinomas (SQC) than in controls (P = .02). The G/G homozygous genotype in COMT rs4680 and A/A homozygous genotype in PLCH1 rs181696 were associated with ADC and SQC, respectively (odds ratio [OR] 0.61 and OR 2.01, respectively). CONCLUSION: In this study, we found that the COMT rs4680 SNP was significantly associated with a reduced risk of NSCLC, especially ADC, which suggests that this SNP may have a protective effect. Moreover, the PLCH1 rs181696 SNP was strongly associated with an increased risk of SQC, which suggests that this SNP may be a risk factor for developing SQC.


Assuntos
Adenocarcinoma/genética , Carcinoma Pulmonar de Células não Pequenas/genética , Carcinoma de Células Escamosas/genética , Catecol O-Metiltransferase/genética , Neoplasias Pulmonares/genética , Fosfoinositídeo Fosfolipase C/genética , Esteroide 17-alfa-Hidroxilase/genética , Adulto , Idoso , Idoso de 80 Anos ou mais , Povo Asiático/genética , Estudos de Casos e Controles , Distribuição de Qui-Quadrado , China , Intervalos de Confiança , Feminino , Genótipo , Humanos , Masculino , Pessoa de Meia-Idade , Razão de Chances , Polimorfismo de Nucleotídeo Único , Fatores de Risco , Fumar
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