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1.
J Invasive Cardiol ; 34(2): E80-E86, 2022 02.
Artigo em Inglês | MEDLINE | ID: mdl-35058374

RESUMO

BACKGROUND AND OBJECTIVES: Long 48 mm drug-eluting stents (DES) used to treat long coronary lesions decreases the number of stents needed and avoids stent overlapping. Disadvantages include difficulty in delivery and size discrepancy between proximal and distal stent landing zones. The present study analyzed the rate of procedural, immediate angiographic, and 1-year clinical outcomes of long diffuse coronary artery lesions treated with 48 mm everolimus-eluting stents (EES) and compared the clinical outcomes with multiple overlapping DES. METHODS: This retrospective analysis included 213 patients with 228 lesions treated with at least one 48 mm EES at 2 hospitals in Taiwan. RESULTS: About 40.4% of the lesions had moderate-severe calcification and 20.2% had acute angulation. The mean lesion length was 49.2 ± 18.1 mm. In 161 lesions requiring a single 48 mm EES, 67.1% had a discrepancy between proximal and distal reference diameter of ≥0.5 mm and 36% had a discrepancy of ≥1.0 mm. The procedural success rate was 98.6%. Target-vessel failure (TVF) rate at 1 year was 4.2%. Cardiac death occurred in 3 patients. The rates of target-vessel myocardial infarction (TV-MI), target-vessel revascularization (TVR) and definite/ probable stent thrombosis were 1.4%, 3.3%, and 0.9%, respectively. After adjusting patient variables by propensity score matching, no significant difference was found for cardiac death, TVF, TV-MI, and clinically driven TVR. CONCLUSION: Use of 48 mm EES to treat long coronary lesions in clinically and anatomically complex patients is safe and effective. In the propensity score-matched analysis, the 48 mm EES and multiple stents have comparable clinical outcomes.


Assuntos
Doença da Artéria Coronariana , Stents Farmacológicos , Infarto do Miocárdio , Intervenção Coronária Percutânea , Doença da Artéria Coronariana/diagnóstico , Doença da Artéria Coronariana/tratamento farmacológico , Doença da Artéria Coronariana/cirurgia , Vasos Coronários/diagnóstico por imagem , Vasos Coronários/cirurgia , Morte , Everolimo/farmacologia , Everolimo/uso terapêutico , Humanos , Estimativa de Kaplan-Meier , Infarto do Miocárdio/etiologia , Intervenção Coronária Percutânea/efeitos adversos , Desenho de Prótese , Estudos Retrospectivos , Sirolimo/uso terapêutico , Stents , Resultado do Tratamento
2.
Nat Neurosci ; 24(8): 1077-1088, 2021 08.
Artigo em Inglês | MEDLINE | ID: mdl-34059832

RESUMO

Nucleocytoplasmic transport (NCT) decline occurs with aging and neurodegeneration. Here, we investigated the NCT pathway in models of amyotrophic lateral sclerosis-fused in sarcoma (ALS-FUS). Expression of ALS-FUS led to a reduction in NCT and nucleoporin (Nup) density within the nuclear membrane of human neurons. FUS and Nups were found to interact independently of RNA in cells and to alter the phase-separation properties of each other in vitro. FUS-Nup interactions were not localized to nuclear pores, but were enriched in the nucleus of control neurons versus the cytoplasm of mutant neurons. Our data indicate that the effect of ALS-linked mutations on the cytoplasmic mislocalization of FUS, rather than on the physiochemical properties of the protein itself, underlie our reported NCT defects. An aberrant interaction between mutant FUS and Nups is underscored by studies in Drosophila, whereby reduced Nup expression rescued multiple toxic FUS-induced phenotypes, including abnormal nuclear membrane morphology in neurons.


Assuntos
Transporte Ativo do Núcleo Celular/fisiologia , Neurônios/metabolismo , Complexo de Proteínas Formadoras de Poros Nucleares/metabolismo , Proteína FUS de Ligação a RNA/metabolismo , Esclerose Lateral Amiotrófica/genética , Esclerose Lateral Amiotrófica/metabolismo , Animais , Animais Geneticamente Modificados , Drosophila , Humanos , Mutação , Proteína FUS de Ligação a RNA/genética
3.
Front Physiol ; 11: 648, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32625116

RESUMO

Visual attack for prey capture in cuttlefish involves three well characterized sequential stages: attention, positioning, and seizure. This visually guided behavior requires accurate sensorimotor integration of information on the target's direction and tentacular strike control. While the behavior of cuttlefish visual attack on a stationary prey has been described qualitatively, the kinematics of visual attack on a moving target has not been analyzed quantitatively. A servomotor system controlling the movement of a shrimp prey and a high resolution imaging system recording the behavior of the cuttlefish predator, together with the newly developed DeepLabCut image processing system, were used to examine the tactics used by cuttlefish during a visual attack on moving prey. The results showed that cuttlefish visually tracked a moving prey target using mainly body movement, and that they maintained a similar speed to that of the moving prey right before making their tentacular strike. When cuttlefish shot out their tentacles for prey capture, they were able to either predict the target location based on the prey's speed and compensate for the inherent sensorimotor delay or adjust the trajectory of their tentacular strike according to the prey's direction of movement in order to account for any changes in prey position. These observations suggest that cuttlefish use the various visual tactics available to them flexibly in order to capture moving prey, and that they are able to extract direction and speed information from moving prey in order to allow an accurate visual attack.

4.
J Biol Chem ; 294(26): 10194-10210, 2019 06 28.
Artigo em Inglês | MEDLINE | ID: mdl-31092554

RESUMO

Excitotoxic levels of glutamate represent a physiological stress that is strongly linked to amyotrophic lateral sclerosis (ALS) and other neurological disorders. Emerging evidence indicates a role for neurodegenerative disease-linked RNA-binding proteins (RBPs) in the cellular stress response. However, the relationships between excitotoxicity, RBP function, and disease have not been explored. Here, using primary cortical and motor neurons, we found that excitotoxicity induced the translocation of select ALS-linked RBPs from the nucleus to the cytoplasm within neurons. RBPs affected by excitotoxicity included TAR DNA-binding protein 43 (TDP-43) and, most robustly, fused in sarcoma/translocated in liposarcoma (FUS/TLS or FUS). We noted that FUS is translocated through a calcium-dependent mechanism and that its translocation coincides with striking alterations in nucleocytoplasmic transport. Furthermore, glutamate-induced up-regulation of glutamate ionotropic receptor α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA)-type subunit 2 (GRIA2) in neurons depended on FUS expression, consistent with a functional role for FUS in excitotoxic stress. These findings reveal molecular links among prominent factors in neurodegenerative diseases, namely excitotoxicity, disease-associated RBPs, and nucleocytoplasmic transport.


Assuntos
Cálcio/metabolismo , Núcleo Celular/metabolismo , Ácido Glutâmico/efeitos adversos , RNA Mensageiro/metabolismo , Proteína FUS de Ligação a RNA/metabolismo , Receptores de AMPA/metabolismo , Estresse Fisiológico , Transporte Ativo do Núcleo Celular , Esclerose Lateral Amiotrófica , Citoplasma , Demência Frontotemporal , Humanos , Mutação , Neurônios/efeitos dos fármacos , Neurônios/metabolismo , Neurônios/patologia , Processamento Pós-Transcricional do RNA , RNA Mensageiro/genética , Proteína FUS de Ligação a RNA/genética , Receptores de AMPA/genética
5.
Hum Mol Genet ; 28(13): 2143-2160, 2019 07 01.
Artigo em Inglês | MEDLINE | ID: mdl-30806671

RESUMO

Aberrant translational repression is a feature of multiple neurodegenerative diseases. The association between disease-linked proteins and stress granules further implicates impaired stress responses in neurodegeneration. However, our knowledge of the proteins that evade translational repression is incomplete. It is also unclear whether disease-linked proteins influence the proteome under conditions of translational repression. To address these questions, a quantitative proteomics approach was used to identify proteins that evade stress-induced translational repression in arsenite-treated cells expressing either wild-type or amyotrophic lateral sclerosis (ALS)-linked mutant FUS. This study revealed hundreds of proteins that are actively synthesized during stress-induced translational repression, irrespective of FUS genotype. In addition to proteins involved in RNA- and protein-processing, proteins associated with neurodegenerative diseases such as ALS were also actively synthesized during stress. Protein synthesis under stress was largely unperturbed by mutant FUS, although several proteins were found to be differentially expressed between mutant and control cells. One protein in particular, COPBI, was downregulated in mutant FUS-expressing cells under stress. COPBI is the beta subunit of the coat protein I (COPI), which is involved in Golgi to endoplasmic reticulum (ER) retrograde transport. Further investigation revealed reduced levels of other COPI subunit proteins and defects in COPBI-relatedprocesses in cells expressing mutant FUS. Even in the absence of stress, COPBI localization was altered in primary and human stem cell-derived neurons expressing ALS-linked FUS variants. Our results suggest that Golgi to ER retrograde transport may be important under conditions of stress and is perturbed upon the expression of disease-linked proteins such as FUS.


Assuntos
Esclerose Lateral Amiotrófica/genética , Retículo Endoplasmático/metabolismo , Complexo de Golgi/metabolismo , Neurônios Motores/metabolismo , Biossíntese de Proteínas , Proteína FUS de Ligação a RNA/genética , Esclerose Lateral Amiotrófica/metabolismo , Animais , Arsenitos/farmacologia , Linhagem Celular Tumoral , Complexo I de Proteína do Envoltório/metabolismo , Grânulos Citoplasmáticos/efeitos dos fármacos , Grânulos Citoplasmáticos/metabolismo , Retículo Endoplasmático/efeitos dos fármacos , Complexo de Golgi/efeitos dos fármacos , Humanos , Camundongos , Neurônios Motores/efeitos dos fármacos , Mutação , Biossíntese de Proteínas/efeitos dos fármacos , Proteômica , Proteína FUS de Ligação a RNA/metabolismo
6.
Carbohydr Polym ; 206: 664-673, 2019 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-30553371

RESUMO

An in situ forming gel based on simply blending carboxymethyl hexanoyl chitosan (CHC) with low molecular weight hyaluronic acid (LMW HA) was developed, without needing cross-linking, photopolymerization or thermal treatments. The CHC/LMW HA blends formed nanoparticles and then rapidly transformed into supermolecular hydrogels under stirring. The gel formation mechanism was examined by Förster resonance energy transfer (FRET). The gels were injectable, cytocompatible and biodegradable, and showed shape-persistent behavior and adhesive property. Berberine, an anti-apoptotic and anti-arthritis naturally occurring compound, was encapsulated within the CHC/LMW HA gels. The gels demonstrated a pH-responsive characteristic which were able to release berberine in a sustained manner at pH 6.0 (simulating inflamed arthritic articular cartilage) and the degradation rates were accelerated at pH 7.4 (simulating healed normal tissue). The berberine-loaded gels effectively protected chondrocytes against sodium nitroprusside-induced apoptosis. The gels may be potentially useful as an injectable system for intra-articular drug delivery and cartilage tissue engineering.


Assuntos
Berberina/farmacologia , Quitosana/análogos & derivados , Preparações de Ação Retardada/química , Géis/química , Ácido Hialurônico/química , Apoptose/efeitos dos fármacos , Células Cultivadas , Quitosana/síntese química , Quitosana/química , Quitosana/toxicidade , Condrócitos/efeitos dos fármacos , Coloides/síntese química , Coloides/química , Coloides/toxicidade , Preparações de Ação Retardada/síntese química , Preparações de Ação Retardada/toxicidade , Géis/síntese química , Géis/toxicidade , Humanos , Ácido Hialurônico/síntese química , Ácido Hialurônico/toxicidade , Concentração de Íons de Hidrogênio , Nanopartículas/química , Nanopartículas/toxicidade , Nitroprussiato , Tamanho da Partícula
7.
IEEE Trans Image Process ; 26(7): 3303-3316, 2017 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-28212082

RESUMO

Due to the unprecedented growth of unedited videos, finding highlights relevant to a text query in a set of unedited videos has become increasingly important. We refer this task as semantic highlight retrieval and propose a query-dependent video representation for retrieving a variety of highlights. Our method consists of two parts: 1) "viralets", a mid-level representation bridging between semantic [Fig. 1(a)] and visual [Fig. 1(c)] spaces and 2) a novel Semantic-MODulation (SMOD) procedure to make viralets query-dependent (referred to as SMOD viralets). Given SMOD viralets, we train a single highlight ranker to predict the highlightness of clips with respect to a variety of queries (two examples in Fig. 1), whereas existing approaches can be applied only in a few predefined domains. Other than semantic highlight retrieval, viralets can also be used to associate relevant terms to each video. We utilize this property and propose a simple term prediction method based on nearest neighbor search. To conduct experiments, we collect a viral video dataset including users' comments, highlights, and/or original videos. Among a testing database with 1189 clips (13% highlights and 87% non-highlights), our highlight ranker achieves 41.2% recall at top-10 retrieved clips. It is significantly higher than the state-of-the-art domain-specific highlight ranker and its extension. Similarly, our method also outperforms all baseline methods on the publicly available video highlight dataset. Finally, our simple term prediction method utilizing viralets outperforms the state-of-the-art matrix factorization method (adapted from Kalayeh et al.). Viral videos refer to popular online videos. We focus on user-generated viral videos, which typically contain short highlight marked by users.

8.
Int J Cardiol ; 222: 104-112, 2016 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-27494721

RESUMO

BACKGROUND: Atrial fibrillation (AF) causes atrial remodeling, and the left atrium (LA) is the favored substrate for maintaining AF. It remains unclear if AF remodels both atria differently and contributes to LA arrhythmogenesis and thrombogenesis. Therefore, we wished to characterize the transcript profiles in the LA and right atrium (RA) in sinus rhythm (SR) and AF respectively. METHODS: Paired LA and RA appendages acquired from patients receiving cardiac surgery were used for ion-channel- and whole-exome-based transcriptome analysis. The ultrastructure was evaluated by immunohistochemistry. RESULTS: Twenty-two and twenty ion-channels and transporters were differentially expressed between the LA and RA in AF and SR, respectively. Among these, 15 genes were differentially expressed in parallel between AF and SR. AF was associated with increased LA/RA expression ratio in 9 ion channel-related genes, including genes related to calcium handling. In microarray, AF was associated with a differential LA/RA gene expression ratio in 309 genes, and was involved in atherosclerosis-related signaling. AF was associated with the upregulation of thrombogenesis-related genes in the LA appendage, including P2Y12, CD 36 and ApoE. Immunohistochemistry showed higher expressions of collagen-1, oxidative stress and TGF-ß1 in the RA compared to the LA. CONCLUSIONS: AF was associated with differential LA-to-RA gene expression related to specific ion channels and pathways as well as upregulation of thrombogenesis-related genes in the LA appendage. Targeting the molecular mechanisms underlying the LA-to-RA difference and AF-related remodeling in the LA appendage may help provide new therapeutic options in treating AF and preventing thromboembolism in AF.


Assuntos
Apêndice Atrial , Fibrilação Atrial , Remodelamento Atrial/genética , Sinalização do Cálcio/genética , Transdução de Sinais/genética , Trombose/genética , Idoso , Apolipoproteínas E/genética , Apêndice Atrial/patologia , Apêndice Atrial/fisiopatologia , Fibrilação Atrial/genética , Fibrilação Atrial/metabolismo , Fibrilação Atrial/patologia , Feminino , Perfilação da Expressão Gênica/métodos , Humanos , Masculino , Pessoa de Meia-Idade , Receptores Purinérgicos P2Y12/genética , ATPases Transportadoras de Cálcio do Retículo Sarcoplasmático/genética , Fator de Crescimento Transformador beta1/genética
9.
Biochem Biophys Res Commun ; 473(1): 243-248, 2016 Apr 22.
Artigo em Inglês | MEDLINE | ID: mdl-27005821

RESUMO

During DNA replication, bacterial helicase is recruited as a complex in association with loader proteins to unwind the parental duplex. Previous structural studies have reported saturated 6:6 helicase-loader complexes with different conformations. However, structural information on the sub-stoichiometric conformations of these previously-documented helicase-loader complexes remains elusive. Here, with the aid of single particle electron-microscopy (EM) image reconstruction, we present the Geobacillus kaustophilus HTA426 helicase-loader (DnaC-DnaI) complex with a 6:2 binding stoichiometry in the presence of ATPγS. In the 19 Šresolution EM map, the undistorted and unopened helicase ring holds a robust loader density above the C-terminal RecA-like domain. Meanwhile, the path of the central DNA binding channel appears to be obstructed by the reconstructed loader density, implying its potential role as a checkpoint conformation to prevent the loading of immature complex onto DNA. Our data also reveals that the bound nucleotides and the consequently induced conformational changes in the helicase hexamer are essential for active association with loader proteins. These observations provide fundamental insights into the formation of the helicase-loader complex in bacteria that regulates the DNA replication process.


Assuntos
Proteínas de Bactérias/química , DNA Helicases/química , Escherichia coli/metabolismo , Geobacillus/enzimologia , Trifosfato de Adenosina/análogos & derivados , Trifosfato de Adenosina/química , Sítios de Ligação , Replicação do DNA , DNA de Cadeia Simples/química , Proteínas de Escherichia coli/química , Hidrólise , Processamento de Imagem Assistida por Computador , Microscopia Eletrônica , Nucleotídeos/genética , Ligação Proteica , Estrutura Terciária de Proteína
10.
Circ Res ; 117(4): e41-e53, 2015 Jul 31.
Artigo em Inglês | MEDLINE | ID: mdl-26034042

RESUMO

RATIONALE: PhosPhatidic Acid Phosphatase type 2B (PPAP2B), an integral membrane protein known as lipid phosphate phosphatase (LPP3) that inactivates lysophosphatidic acid, was implicated in coronary artery disease (CAD) by genome-wide association studies. However, it is unclear whether genome-wide association studies-identified coronary artery disease genes, including PPAP2B, participate in mechanotransduction mechanisms by which vascular endothelia respond to local atherorelevant hemodynamics that contribute to the regional nature of atherosclerosis. OBJECTIVE: To establish the critical role of PPAP2B in endothelial responses to hemodynamics. METHODS AND RESULTS: Reduced PPAP2B was detected in vivo in mouse and swine aortic arch (AA) endothelia exposed to chronic disturbed flow, and in mouse carotid artery endothelia subjected to surgically induced acute disturbed flow. In humans, PPAP2B was reduced in the downstream part of carotid plaques where low shear stress prevails. In culture, reduced PPAP2B was measured in human aortic endothelial cells under atherosusceptible waveform mimicking flow in human carotid sinus. Flow-sensitive microRNA-92a and transcription factor KLF2 were identified as upstream inhibitor and activator of endothelial PPAP2B, respectively. PPAP2B suppression abrogated atheroprotection of unidirectional flow; inhibition of lysophosphatidic acid receptor 1 restored the flow-dependent, anti-inflammatory phenotype in PPAP2B-deficient cells. PPAP2B inhibition resulted in myosin light-chain phosphorylation and intercellular gaps, which were abolished by lysophosphatidic acid receptor 1/2 inhibition. Expression quantitative trait locus mapping demonstrated PPAP2B coronary artery disease risk allele is not linked to PPAP2B expression in various human tissues but significantly associated with reduced PPAP2B in human aortic endothelial cells. CONCLUSIONS: Atherorelevant flows dynamically modulate endothelial PPAP2B expression through miR-92a and KLF2. Mechanosensitive PPAP2B plays a critical role in promoting anti-inflammatory phenotype and maintaining vascular integrity of endothelial monolayer under atheroprotective flow.


Assuntos
Aorta Torácica/enzimologia , Aterosclerose/enzimologia , Células Endoteliais/enzimologia , Hemodinâmica , Mecanotransdução Celular , Fosfatidato Fosfatase/metabolismo , Regiões 3' não Traduzidas , Animais , Aorta Torácica/fisiopatologia , Aterosclerose/genética , Aterosclerose/fisiopatologia , Aterosclerose/prevenção & controle , Sítios de Ligação , Células Cultivadas , Regulação Enzimológica da Expressão Gênica , Frequência do Gene , Predisposição Genética para Doença , Estudo de Associação Genômica Ampla , Humanos , Fatores de Transcrição Kruppel-Like/metabolismo , Camundongos , MicroRNAs/metabolismo , Cadeias Leves de Miosina/metabolismo , Fenótipo , Fosfatidato Fosfatase/genética , Fosforilação , Interferência de RNA , Receptores de Ácidos Lisofosfatídicos/metabolismo , Fluxo Sanguíneo Regional , Estresse Mecânico , Suínos , Fatores de Tempo , Transfecção
11.
J Neurochem ; 131(4): 407-12, 2014 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-25053581

RESUMO

The deposition of amyloid-ß (Aß) peptide, which is generated from amyloid precursor protein (APP), is the pathological hallmark of Alzheimer's disease (AD). Three APP familial AD mutations (D678H, D678N, and H677R) located at the sixth and seventh amino acid of Aß have distinct effect on Aß aggregation, but their influence on the physiological and pathological roles of APP remain unclear. We found that the D678H mutation strongly enhances amyloidogenic cleavage of APP, thus increasing the production of Aß. This enhancement of amyloidogenic cleavage is likely because of the acceleration of APPD678H sorting into the endosomal-lysosomal pathway. In contrast, the APPD678N and APPH677R mutants do not cause the same effects. Therefore, this study indicates a regulatory role of D678H in APP sorting and processing, and provides genetic evidence for the importance of APP sorting in AD pathogenesis. The internalization of amyloid precursor protein (APP) increases its opportunity to be processed by ß-secretase and to produce Amyloid-ß (Aß) that causes Alzheimer's disease (AD). We report a pathogenic APPD678H mutant that enhances APP internalization into the endosomal-lysosomal pathway and thus promotes the ß-secretase cleavage and Aß production. This study provides genetic evidence for the importance of APP sorting in AD pathogenesis.


Assuntos
Doença de Alzheimer/genética , Peptídeos beta-Amiloides/metabolismo , Precursor de Proteína beta-Amiloide/genética , Precursor de Proteína beta-Amiloide/metabolismo , Mutação/genética , Cloreto de Amônio/farmacologia , Biotinilação , Células HEK293 , Humanos , Lisossomos/efeitos dos fármacos , Lisossomos/genética , Lisossomos/metabolismo , Fragmentos de Peptídeos/metabolismo , Transporte Proteico/efeitos dos fármacos , Transporte Proteico/genética , Transfecção
12.
Clin Rheumatol ; 33(1): 91-8, 2014 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-23990026

RESUMO

Large epidemiologic studies have associated gouty arthritis with the risk of coronary heart disease. However, there has been a lack of information regarding the outcomes for patients who have gout attacks during hospitalization for acute myocardial infarction. We reviewed the data of 444 consecutive patients who were admitted to our hospital between 2005 and 2008 due to acute ST elevation myocardial infarction (STEMI). The clinical outcomes were compared between patients with gout attack and those without. Of the 444, 48 patients with acute STEMI developed acute gouty arthritis during hospitalization. The multivariate analysis identified prior history of gout and estimated glomerular filtration rate as independent risk factors of gout attack for patients with acute STEMI (odds ratio (OR) 21.02, 95 % CI 2.96-149.26, p = 0.002; OR 0.92, 95 % CI 0.86-0.99, p = 0.035, respectively). The in-hospital mortality and duration of hospital stay did not differ significantly between the gouty group and the non-gouty group (controls). During a mean follow-up of 49 ± 28 months, all-cause mortality and stroke were similar for both groups. Multivariate Cox regression showed that gout attack was independently associated with short- and long-term adverse non-fatal cardiac events (hazard ratio (HR) 1.88, 95 % CI 1.09-3.24, p = 0.024; HR 1.82, 95 % CI 1.09-3.03, p = 0.022, respectively). Gout attack among patients hospitalized due to acute STEMI was independently associated with short-term and long-term rates of adverse non-fatal cardiac events.


Assuntos
Artrite Gotosa/diagnóstico , Infarto do Miocárdio/diagnóstico , Idoso , Artrite Gotosa/complicações , Feminino , Taxa de Filtração Glomerular , Cardiopatias/complicações , Cardiopatias/mortalidade , Hospitalização , Humanos , Masculino , Pessoa de Meia-Idade , Análise Multivariada , Infarto do Miocárdio/complicações , Razão de Chances , Modelos de Riscos Proporcionais , Análise de Regressão , Estudos Retrospectivos , Fatores de Risco , Fatores de Tempo , Resultado do Tratamento
13.
Opt Lett ; 38(2): 184-6, 2013 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-23454956

RESUMO

In recent years, researchers have demonstrated negative refraction theoretically and experimentally by pumping optical power into photonic crystal (PhC) or waveguide structures. The concept of negative refraction can be used to create a perfect lens that focuses an object smaller than the wavelength. By inserting two-dimensional PhCs into the peripheral of a semiconductor light emitting structure, this study presents an electroluminescent device with negative refraction in the visible wavelength range. This approach produces polarization dependent collimation behavior in far-field radiation patterns. The modal dispersion of negative refraction results in strong group velocity modulation, and self-focusing and -defocusing behaviors are apparent from light extraction. This study further verifies experimental results by using theoretic calculations based on equifrequency contours.

14.
EMBO J ; 31(17): 3575-87, 2012 Aug 29.
Artigo em Inglês | MEDLINE | ID: mdl-22850672

RESUMO

In mammals, a distinct RNA polymerase II form, RNAPII(G) contains a novel subunit Gdown1 (encoded by POLR2M), which represses gene activation, only to be reversed by the multisubunit Mediator co-activator. Here, we employed single-particle cryo-electron microscopy (cryo-EM) to disclose the architectures of RNAPII(G), RNAPII and RNAPII in complex with the transcription initiation factor TFIIF, all to ~19 Å. Difference analysis mapped Gdown1 mostly to the RNAPII Rpb5 shelf-Rpb1 jaw, supported by antibody labelling experiments. These structural features correlate with the moderate increase in the efficiency of RNA chain elongation by RNAP II(G). In addition, our updated RNAPII-TFIIF map showed that TFIIF tethers multiple regions surrounding the DNA-binding cleft, in agreement with cross-linking and biochemical mapping. Gdown1's binding sites overlap extensively with those of TFIIF, with Gdown1 sterically excluding TFIIF from RNAPII, herein demonstrated by competition assays using size exclusion chromatography. In summary, our work establishes a structural basis for Gdown1 impeding initiation at promoters, by obstruction of TFIIF, accounting for an additional dependent role of Mediator in activated transcription.


Assuntos
RNA Polimerase II/metabolismo , Fatores de Transcrição TFII/metabolismo , Animais , Ligação Competitiva , Bovinos , Cromatografia em Gel , Microscopia Crioeletrônica , Conformação Proteica , RNA Polimerase II/química , RNA Polimerase II/ultraestrutura , Proteínas Recombinantes/química , Proteínas Recombinantes/metabolismo , Proteínas Recombinantes/ultraestrutura , Fatores de Transcrição TFII/química , Fatores de Transcrição TFII/ultraestrutura , Transcrição Gênica
15.
Intern Med ; 51(14): 1815-20, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-22821093

RESUMO

OBJECTIVE: We aimed to investigate the association between the ABO blood groups and the risk of coronary artery disease (CAD) and myocardial infartion (MI) in a young Taiwanese population. METHODS: We retrospectively recruited 277 consecutive subjects (men younger than 45 years and women younger than 55 years) who underwent coronary angiography (136 with documented CAD and 129 without CAD) at our center, between 2005 and 2008. Their ABO blood groups were determined using standard agglutination techniques. RESULTS: Patients with CAD showed a significantly different blood group distribution (O, 30.1%; A, 39.7%; B, 26.5%; AB, 3.7%) than that shown by the controls (O, 42.6%; A, 24.0%; B, 27.1%; AB, 6.2%; p=0.032). Patients with blood group A had a greater risk of CAD and MI than those with non-A blood groups (OR=2.08, 95% CI=1.23-3.54; OR=2.21, 95% CI=1.19-4.09, respectively). After adjustment for common cardiovascular risk factors such as age, gender, hypertension, cigarette smoking, diabetes mellitus, body mass index, family history of CAD, and lipid profiles; blood group A remained significantly associated with an increased risk of CAD and MI (OR=2.61, 95% CI 1.11-6.14, p=0.028; OR=3.53, 95% CI=1.21-10.29, p=0.021, respectively). CONCLUSION: Our findings suggest that blood group A is an independent risk factor for CAD and MI in young people in Taiwan.


Assuntos
Sistema ABO de Grupos Sanguíneos , Doença da Artéria Coronariana/sangue , Adulto , Estudos de Casos e Controles , Doença da Artéria Coronariana/epidemiologia , Feminino , Humanos , Lipídeos/sangue , Modelos Logísticos , Masculino , Pessoa de Meia-Idade , Infarto do Miocárdio/sangue , Infarto do Miocárdio/epidemiologia , Fatores de Risco , Taiwan/epidemiologia
16.
PLoS One ; 7(7): e40226, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-22792246

RESUMO

Lon proteases are a family of ATP-dependent proteases involved in protein quality control, with a unique proteolytic domain and an AAA(+) (ATPases associated with various cellular activities) module accommodated within a single polypeptide chain. They were classified into two types as either the ubiquitous soluble LonA or membrane-inserted archaeal LonB. In addition to the energy-dependent forms, a number of medically and ecologically important groups of bacteria encode a third type of Lon-like proteins in which the conserved proteolytic domain is fused to a large N-terminal fragment lacking canonical AAA(+) motifs. Here we showed that these Lon-like proteases formed a clade distinct from LonA and LonB. Characterization of one such Lon-like protease from Meiothermus taiwanensis indicated that it formed a hexameric assembly with a hollow chamber similar to LonA/B. The enzyme was devoid of ATPase activity but retained an ability to bind symmetrically six nucleotides per hexamer; accordingly, structure-based alignment suggested possible existence of a non-functional AAA-like domain. The enzyme degraded unstructured or unfolded protein and peptide substrates, but not well-folded proteins, in ATP-independent manner. These results highlight a new type of Lon proteases that may be involved in breakdown of excessive damage or unfolded proteins during stress conditions without consumption of energy.


Assuntos
Protease La/química , Desdobramento de Proteína , Adenosina Trifosfatases/metabolismo , Sequência de Aminoácidos , Deinococcus/enzimologia , Ativação Enzimática , Hidrólise , Magnésio/metabolismo , Modelos Moleculares , Dados de Sequência Molecular , Nucleotídeos/metabolismo , Protease La/classificação , Protease La/genética , Protease La/metabolismo , Ligação Proteica , Conformação Proteica , Alinhamento de Sequência
17.
J Am Chem Soc ; 134(24): 10011-20, 2012 Jun 20.
Artigo em Inglês | MEDLINE | ID: mdl-22646012

RESUMO

The finding of new metal alloyed nanocrystals (NCs) with high catalytic activity and low cost to replace PtRu NCs is a critical step toward the commercialization of fuel cells. In this work, a simple cation replacement reaction was utilized to synthesize a new type of ternary Fe(1-x)PtRu(x) NCs from binary FePt NCs. The detailed structural transformation from binary FePt NCs to ternary Fe(1-x)PtRu(x) NCs was analyzed by X-ray absorption spectroscopy (XAS). Ternary Fe(35)Pt(40)Ru(25), Fe(31)Pt(40)Ru(29), and Fe(17)Pt(40)Ru(43) NCs exhibit superior catalytic ability to withstand CO poisoning in methanol oxidation reaction (MOR) than do binary NCs (FePt and J-M PtRu). Also, the Fe(31)Pt(40)Ru(29) NCs had the highest alloying extent and the lowest onset potential among the ternary NCs. Furthermore, the origin for the superior CO resistance of ternary Fe(1-x)PtRu(x) NCs was investigated by determining the adsorption energy of CO on the NCs' surfaces and the charge transfer from Fe/Ru to Pt using a simulation based on density functional theory. The simulation results suggested that by introducing a new metal into binary PtRu/PtFe NCs, the anti-CO poisoning ability of ternary Fe(1-x)PtRu(x) NCs was greatly enhanced because the bonding of CO-Pt on the NCs' surface was weakened. Overall, our experimental and simulation results have indicated a simple route for the discovery of new metal alloyed catalysts with superior anti-CO poisoning ability and low usage of Pt and Ru for fuel cell applications.

18.
Tex Heart Inst J ; 39(1): 112-5, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-22412243

RESUMO

A large-lumen guiding catheter is often used for complex percutaneous coronary intervention-particularly when a final kissing-balloon or 2-stent technique is required. However, catheter insertion is sometimes restricted by diseased vascular access sites or a tortuous vascular route.We report 2 cases in which a unique double guiding catheter technique was used to create a lumen of sufficient size for complex percutaneous coronary intervention. In each patient, two 6F guiding catheters were used concurrently to engage the ostium of 1 target vessel. In 1 patient, these catheters were used for the delivery of 2 balloons to complete kissing-balloon dilation after single-stent placement. In the other patient, the catheters were used to deliver 2 stents sequentially to their respective target lesions. The stents were then deployed simultaneously as kissing stents, followed by high-pressure kissing-balloon postdilation.


Assuntos
Angioplastia Coronária com Balão/instrumentação , Catéteres , Oclusão Coronária/terapia , Estenose Coronária/terapia , Idoso , Angiografia Coronária , Oclusão Coronária/diagnóstico por imagem , Estenose Coronária/diagnóstico por imagem , Stents Farmacológicos , Desenho de Equipamento , Feminino , Humanos , Masculino , Desenho de Prótese , Resultado do Tratamento
19.
J Emerg Med ; 42(1): 28-35, 2012 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-19062231

RESUMO

BACKGROUND: Acute post-traumatic ST-elevation myocardial infarction (STEMI) is rare but potentially disastrous in patients with blunt cardiac injury. Sometimes the diagnosis is delayed. Failed myocardial salvage by percutaneous coronary intervention (PCI) within 9 h after the onset of post-traumatic STEMI has been described. OBJECTIVE: We present a case report of a patient in whom effective myocardial salvage with PCI was obtained in a late diagnosed acute post-traumatic STEMI. CASE REPORT: We report the case of a young man who was involved in a motorcycle crash, who had a delayed diagnosis of post-traumatic STEMI. Diagnostic coronary angiography was performed to guide treatment strategy. An occluded left anterior descending artery due to a dissection, and an intimal flap at the first diagonal branch were found. A PCI was done 18 h after the onset of the event with striking and immediate improvement of the regional left ventricular wall motion and ejection fraction. CONCLUSION: After blunt thoracic injury, there is the possibility of an acute post-traumatic STEMI being present when facing a patient with clues of blunt cardiac injury. If the diagnosis of acute post-traumatic STEMI is clinically strong, the patient should be managed individually according to the clinical scenario. Early recognition and prompt management are vital when dealing with patients suffering post-traumatic STEMI.


Assuntos
Angioplastia Coronária com Balão/métodos , Infarto do Miocárdio/terapia , Doença Aguda , Adulto , Diagnóstico Tardio , Eletrocardiografia , Serviço Hospitalar de Emergência , Humanos , Masculino , Infarto do Miocárdio/diagnóstico , Terapia de Salvação/métodos , Resultado do Tratamento
20.
Nanoscale ; 2(4): 573-81, 2010 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-20644761

RESUMO

We present the controlled synthesis of bimetallic Pt(x)Fe(1-x) nanoparticles with tunable physical properties and a study of their catalytic activity towards the oxygen reduction reaction (ORR). Composition-induced variations in alloying extent and Pt d-band vacancies in Pt-Fe/C catalysts are systematically investigated. Density functional theoretical calculations are performed in order to realize the electronic effect caused by alloying Pt with Fe. The DFT computational observations revealed that iron donates electrons to platinum, when the Fe 3d and Pt 5d orbitals undergo hybridization. The Pt(x)Fe(1-x) catalysts with various Pt-to-Fe atomic ratios are characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), cyclic voltammetry (CV), and X-ray absorption spectroscopy (XAS). TEM images indicate that the dispersion of the metal nanoparticles is uniform and the XAS technique provides significant insight on Pt d-band vacancies and the alloying extent of Pt and Fe in Pt(x)Fe(1-x) nanoparticles. Rotating-disk voltammetry of Pt(x)Fe(1-x) nanoparticle catalysts with various Pt : Fe atomic compositions (3 : 1, 1 : 1, and 1 : 3) revealed that the Pt(1)Fe(1)/C nanocatalyst showed a greater enhancement in ORR activity than platinum. The enhanced catalytic activity toward ORR is attributed to the higher alloying extent of platinum and iron as well as the promising electronic structure offered by the lower unfilled Pt d states in Pt(x)Fe(1-x) nanoparticles when compared to pure Pt.


Assuntos
Ferro/química , Oxigênio/química , Platina/química , Catálise , Nanopartículas Metálicas/química , Microscopia Eletrônica de Transmissão , Oxirredução , Espectroscopia por Absorção de Raios X , Difração de Raios X
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