Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 14 de 14
Filtrar
1.
Opt Express ; 17(3): 1636-45, 2009 Feb 02.
Artigo em Inglês | MEDLINE | ID: mdl-19188993

RESUMO

We used a reversal imprinting-in-metal (RIM) process to fabricate various three-dimensional (3D) metal structures under low pressure. Molds featuring different shapes were used to pattern various subwavelength metal structures, including pyramidal, hole-array, and crater-like structures. Refractive index matching and cavity effects both enhanced the degree of transmission of these structured metal films. The crater-like structure appears to be a promising material because of the unique properties imparted by the elongated and gradually tapering spacing of its cavities. From both near-field simulations and experimentally obtained optical spectra, we found that the cavity effect in the crater-like structure led to significantly enhanced transmission of the optical intensity. Thus, this RIM process allows the ready fabrication of various two- and three-dimensional metallic structures for use in surface plasmon-based devices.

2.
Opt Express ; 16(4): 2415-22, 2008 Feb 18.
Artigo em Inglês | MEDLINE | ID: mdl-18542320

RESUMO

In this paper, we describe a thermal embossing imprint method, which we name "nano-imprinting in metal" (NIM), for patterning metal films with a variety of profiles. Metal films exhibiting either perforated hole-arrays or corrugated structures with various surface morphologies can be fabricated rapidly. The SPR phenomenon allowed energy coupling to the other side of the textured metal film, causing a dramatic increase in the transmission. As a technique for readily controlling the working wavelength and transmittance, the NIM method has great potential for application in various optoelectronic devices.

3.
Diabet Med ; 22(12): 1690-5, 2005 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-16401313

RESUMO

AIM: Apolipoprotein AV (APOA5) is an important determinant of plasma triglyceride concentration. This study aimed to investigate the relationship of an amino acid substitution at position 182 (G182C) of the apolipoprotein AV (APOA5) gene with triglyceride concentration in a Taiwanese population. METHODS: This study enrolled two cohorts: non-diabetic subjects (112 males and 89 females) aged 50.3+/-11.0 years (mean+/-sd) and diabetic subjects (106 males and 96 females) aged 62.1+/-10.3 years. The relationship between the G182C polymorphism (rs 2075291) and plasma triglycerides was examined. Demographic and metabolic parameters including age, sex, body mass index, fasting plasma glucose and total cholesterol were also obtained. RESULTS: The G182C polymorphism was a determinant of plasma triglycerides in both non-diabetic (P=0.022) and diabetic (P=0.003) groups, independent of age, gender, fasting plasma glucose, body mass index and total cholesterol. In the diabetic group, this genetic polymorphism interacts significantly (P=0.032) with fasting plasma glucose concentration on plasma triglycerides after adjustment for age, sex, body mass index and total cholesterol. CONCLUSIONS: In conclusion, the G182C polymorphism of the APOA5 gene affects plasma triglycerides in both non-diabetic and diabetic populations. The observed interaction of gene and glycaemic control further indicates a multifactorial nature of clinical phenotypes in subjects with Type 2 diabetes.


Assuntos
Apolipoproteínas/genética , Diabetes Mellitus Tipo 2/genética , Polimorfismo de Nucleotídeo Único/genética , Triglicerídeos/sangue , Adulto , Idoso , Apolipoproteína A-V , Apolipoproteínas A , Estudos de Coortes , Feminino , Predisposição Genética para Doença , Humanos , Masculino , Pessoa de Meia-Idade , Reação em Cadeia da Polimerase , Polimorfismo de Fragmento de Restrição , Taiwan
4.
Diabetologia ; 46(7): 977-83, 2003 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-12827242

RESUMO

AIMS/HYPOTHESIS: Genetic interactions in modulating the phenotypes of a complex trait, such as insulin sensitivity, were usually taken for granted. However, this has not been commonly shown. Previous studies have suggested that both PPARgamma2 and adiponectin genes could influence insulin sensitivity. Therefore it is likely that they could modulate insulin sensitivity through gene to gene interactions. METHODS: We genotyped 1793 subjects of Chinese and Japanese descendents from 601 hypertensive families recruited in Sapphire study for a T94G in the adiponectin gene exon 2 and the PPARgamma2 Pro12Ala polymorphisms. Serum insulin concentrations and insulin resistance index (HOMA(IR)) were used as the markers of insulin sensitivity. RESULTS: We found that the T allele of adiponectin gene was associated with a higher Ins60 and higher area under curve of insulin (AUCi) in OGTT utilizing all subjects in a mixed model that corrected for family effects. Important interactions between adiponectin and PPARgamma2 genotypes were found in fasting insulin concentrations (Ins0), insulin concentrations at 2-h (Ins120) in OGTT and insulin resistance index (HOMA(IR)). The main effects of the PPARgamma2 genotypes were in the plasma glucose concentrations in OGTT. In contrast, the main effects of adiponectin genotypes were in every insulin variable, including Ins0, Ins60, Ins120, AUCi and HOMA(IR). The subjects carrying the adiponectin G allele and the PPARgamma2 Ala12 allele seemed to be more insulin sensitive. CONCLUSION/INTERPRETATION: These results showed that adiponectin is a genetic factor associated with insulin sensitivity. Interactions with PPARgamma2 genotypes modified this association.


Assuntos
Epistasia Genética , Resistência à Insulina/genética , Insulina/sangue , Peptídeos e Proteínas de Sinalização Intercelular , Polimorfismo de Nucleotídeo Único/genética , Proteínas/genética , Receptores Citoplasmáticos e Nucleares/genética , Fatores de Transcrição/genética , Adiponectina , Substituição de Aminoácidos , Área Sob a Curva , Povo Asiático/genética , China , Éxons , Família , Frequência do Gene , Genótipo , Teste de Tolerância a Glucose , Humanos , Hipertensão/genética , Japão , Mutação de Sentido Incorreto , Fenótipo
5.
Chest ; 119(6): 1961-3, 2001 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-11399734

RESUMO

Severe hemolytic anemia in patients with disseminated tuberculosis is exceedingly rare. We report an episode of Coombs'-positive hemolytic anemia in a previously healthy young man with miliary tuberculosis, resulting in a hemoglobin level of 5 g/dL and an undetectable haptoglobin level. The patient responded well to treatment with antituberculosis drugs, and the results of the direct Coombs' test became negative without the need of blood transfusion or steroid therapy.


Assuntos
Anemia Hemolítica Autoimune/etiologia , Tuberculose Miliar/complicações , Tuberculose Miliar/tratamento farmacológico , Adulto , Teste de Coombs , Haptoglobinas/análise , Hemoglobinas/análise , Humanos , Masculino
6.
IEEE Trans Image Process ; 8(8): 1120-4, 1999.
Artigo em Inglês | MEDLINE | ID: mdl-18267526

RESUMO

In this work, discriminative training is studied to improve the performance of our pseudo two-dimensional (2-D) hidden Markov model (PHMM) based text recognition system. The aim of this discriminative training is to adjust model parameters to directly minimize the classification error rate. Experimental results have shown great reduction in recognition error rate even for PHMMs already well-trained using conventional maximum likelihood (ML) approaches.

7.
Eur J Neurosci ; 9(11): 2383-93, 1997 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-9464932

RESUMO

BatK is a second member of the Csk family of regulatory kinases that phosphorylate a key inhibitory tyrosine on Src family kinases, leading to down-regulation. To investigate the roles of BatK and Csk, both of which are expressed in the brain, we compared their temporal expression patterns during development of the central nervous system (CNS) in rats. BatK mRNA is undetectable at embryonic day 12 (E12), appears in the developing nervous system at approximately E15, and its expression progressively increases up to the time of birth, thereafter remaining high throughout the adult brain. In striking contrast, Csk is highly expressed throughout embryonic development and remains high in the CNS until birth. It is then dramatically down-regulated in the adult brain except in the olfactory bulb. BatK and Csk thus exhibit complementary temporal expression patterns. Since BatK expression correlates with late-stage development and terminal differentiation, we speculated that it might be involved in regulating neuronal differentiation. Using PC12 cells as a model system, we show that overexpression of BatK is sufficient to induce neurite outgrowth in the absence of nerve growth factor. Further, overexpression of BatK activates the mitogen-activated protein kinase cascade. We propose a model suggesting that, despite overlapping in vitro activities, BatK and Csk regulate different targets in vivo and have different functions during and after neuronal development, BatK being the dominant regulator of Src kinases in the fully differentiated adult brain.


Assuntos
Sistema Nervoso Central/crescimento & desenvolvimento , Sistema Nervoso Central/metabolismo , Proteínas do Tecido Nervoso/biossíntese , Proteínas Tirosina Quinases/biossíntese , Domínios de Homologia de src , Animais , Antimetabólitos/farmacologia , Southern Blotting , Bromodesoxiuridina/farmacologia , Proteína Tirosina Quinase CSK , Diferenciação Celular/efeitos dos fármacos , Córtex Cerebral/citologia , Córtex Cerebral/metabolismo , Técnica Indireta de Fluorescência para Anticorpo , Vetores Genéticos , Hibridização In Situ , Fatores de Crescimento Neural/fisiologia , Neurônios/metabolismo , Células PC12 , Reação em Cadeia da Polimerase , Proteínas Tirosina Quinases/metabolismo , Proteínas Tirosina Quinases/farmacologia , Ratos , Transfecção , Quinases da Família src
8.
J Cell Physiol ; 161(1): 142-8, 1994 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-7929599

RESUMO

Exposure of non-excitatory cells to the tyrosine kinase (PTK) inhibitors, genistein, herbimycin A, and tyrphostin, induced at least two families of K+ currents. The first, a TEA-insensitive slow-inactivating K+ current, is induced within 3 min following treatment with 140 mM genistein or 100 nM herbimycin A. The second current, a TEA-sensitive delayed rectifier, is induced within 30 min following treatment with 50 mM genistein or 10 nM herbimycin A. Currents with similar biophysical and pharmacological characteristics are induced in these cells following exposure to ionizing radiation. The radiation-induced currents are inhibited by pretreatment with the free radical scavenger, N-Acetyl L-Cysteine, or by pretreatment with the protein kinase C inhibitor, staurosporine; those induced by PTK inhibitors are not. The latter, therefore, do not appear to be mediated through free radicals or require serine/threonine phosphorylation for activation. Once the channels are activated by the PTK inhibitors, phosphorylation of the channel at serine/threonine residues results in slower inactivation of the induced current. We propose that protein tyrosine phosphorylation of the K+ channel protein itself or of a factor that interacts with it maintains the K+ channels of non-excitatory cells in a closed state. Following exposure to ionizing radiation, free radical-induced activation of serine/threonine kinase(s) results in phosphorylation of the channel and/or inactivation of a tyrosine kinase that in turn leads to activation of the K+ channels.


Assuntos
Canais de Potássio/efeitos dos fármacos , Proteínas Tirosina Quinases/antagonistas & inibidores , Acetilcisteína/farmacologia , Alcaloides/farmacologia , Sequência de Aminoácidos , Benzoquinonas , Cálcio/farmacologia , Linhagem Celular , Condutividade Elétrica , Sequestradores de Radicais Livres/farmacologia , Humanos , Immunoblotting , Lactamas Macrocíclicas , Dados de Sequência Molecular , Fosfoproteínas/metabolismo , Canais de Potássio/genética , Canais de Potássio/fisiologia , Quinonas/farmacologia , Rifabutina/análogos & derivados , Estaurosporina
9.
J Neurosci Res ; 38(6): 705-15, 1994 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-7807586

RESUMO

A novel cDNA, brain-associated tyrosine kinase (Batk), was isolated from a rat hippocampal library and appears to encode a new member of the Csk subfamily of non-receptor protein tyrosine kinases, with 52% overall amino acid identity to rat Csk. Batk resembles kinases of the Src family in that it contains a Src homology 2 (SH2) domain and an SH3 domain, followed by a tyrosine kinase domain. Analysis of incompletely spliced Batk cDNAs suggests that the genomic structure of Batk is similar to that of Csk with identical exon/intron boundaries. Batk also shows significant homology (86% overall amino acid identity) to the recently described human megakaryocyte-specific Matk. Although Batk is 41 amino acids shorter than Matk, Southern blot analysis suggests that Batk might be a rat homolog of Matk. Batk is predominantly expressed in the brain, with lower expression in the spleen and undetectable expression in other tissues. In situ hybridization and Northern blot analysis show that Batk is widely distributed throughout the adult brain, being primarily expressed in neurons, including those of the hippocampus and cortex. In contrast, embryos appear to have markedly decreased expression levels. Analysis of postnatal day 1 brain suggests that Batk may be upregulated at birth throughout the brain except in the cerebellum. In view of its homology to Csk, a negative regulator of Src family tyrosine kinases, and its generalized expression in the adult brain, we suggest that Batk may function as a brain-specific regulator of kinases involved in the development and maintenance of the nervous system.


Assuntos
Encéfalo/metabolismo , Proteínas do Tecido Nervoso/química , Proteínas do Tecido Nervoso/isolamento & purificação , Proteínas Tirosina Quinases/química , Proteínas Tirosina Quinases/isolamento & purificação , Proteínas Tirosina Quinases/metabolismo , Quinases da Família src , Sequência de Aminoácidos , Animais , Sequência de Bases , Proteína Tirosina Quinase CSK , Genoma , Sondas Moleculares/genética , Dados de Sequência Molecular , Proteínas do Tecido Nervoso/genética , Proteínas Tirosina Quinases/genética , Ratos , Homologia de Sequência de Aminoácidos
10.
Proc Natl Acad Sci U S A ; 90(3): 908-12, 1993 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-8430104

RESUMO

Active oxygen species are generated during pathophysiologic conditions such as inflammation and ionizing radiation exposure. We tested the hypothesis that an early cellular event in response to these species involves regulation of ion channels. We exposed cells to gamma-irradiation or treated them with hydrogen peroxide, xanthine/xanthine oxidase, or [3H]thymidine and then monitored channel activity by the technique of whole-cell voltage clamping. Recordings showed that both normal and tumor cells exhibit an increase in K+ currents after treatment with radiation, H2O2, and xanthine/xanthine oxidase but not with high specific activity [3H]thymidine, suggesting that the signal for K+ channel activation originates at the cell membrane. A single noncytotoxic dose of 10 cGy induced measurable levels of K+ currents, suggesting that the induction of currents regulates biochemical changes in response to stress. To test whether channel activity is sensitive to active oxygen species, we pretreated cells with N-acetyl-L-cysteine (NAC) to increase cellular pools of free radical scavengers before radiation. In NAC-pretreated cells, K+ channel activation by gamma-irradiation was abolished. It has previously been shown that protein kinase C (PKC) is activated by ionizing radiation and can regulate K+ channels in some cells. However, the effect of radiation on induction of K+ channel activity was independent of PKC, since cells chronically exposed to phorbol esters still produced K+ currents after radiation. These results suggest that an early cellular response to oxidative stress is the activation of K+ channels.


Assuntos
Raios gama , Oxigênio/metabolismo , Canais de Potássio/efeitos da radiação , Potássio/metabolismo , Acetilcisteína/farmacologia , Animais , Linhagem Celular , Relação Dose-Resposta à Radiação , Condutividade Elétrica , Sequestradores de Radicais Livres , Radicais Livres , Peróxido de Hidrogênio/farmacologia , Microeletrodos , Canais de Potássio/efeitos dos fármacos , Canais de Potássio/metabolismo , Proteína Quinase C/metabolismo
11.
Nucleic Acids Res ; 20(6): 1401-4, 1992 Mar 25.
Artigo em Inglês | MEDLINE | ID: mdl-1561096

RESUMO

A method is described for the isolation of chromosome region specific cosmids. The 5q35 region of the long arm of human chromosome 5 was microdissected, digested with MboI, ligated to oligonucleotide adaptors, amplified by the polymerase chain reaction and cloned into a plasmid vector. Inserts which did not contain highly repetitive sequences were used to screen a chromosome 5 cosmid library by direct hybridization. There were 33 positive cosmid clones identified with 4 microclones. Individual cosmid clones were biotinylated and used as probes for fluorescence in situ hybridization to metaphase chromosomes. Of the 33 cosmids that were mapped, 29 localized to q35 and 4 to q34, demonstrating the specificity of the microdissection library and the cosmids.


Assuntos
Cromossomos Humanos Par 5 , Cosmídeos , Sequência de Bases , Southern Blotting , Clonagem Molecular , DNA , Biblioteca Gênica , Humanos , Dados de Sequência Molecular , Hibridização de Ácido Nucleico , Reação em Cadeia da Polimerase
12.
Oncogene ; 6(6): 961-8, 1991 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-2067848

RESUMO

The mouse Lyl-1 gene was cloned and shown to consist of four exons with extensive nucleotide and structural homology to the human LYL1 gene. The Lyl-1 gene was localized to the central region of mouse chromosome 8 which defines a new region of synteny with human chromosome 19p. The predicted mouse Lyl-1 protein is 78% identical to human LYL1. The region of highest similarity occurs in the basic DNA binding and helix-loop-helix dimerization motifs which are nearly identical in mouse and man differing by only one conservative amino acid substitution. Expression of the Lyl-1 gene was found to be low in murine spleen and undetectable in other tissues by Northern blot analysis. In lymphoid cell lines, Lyl-1 was expressed in most B lineage cells but downregulated during terminal differentiation and was not expressed in most T lineage cells. In a human T ALL cell line carrying a translocation that juxtaposed LYL1 with the beta TCR gene, the translocated LYL1 gene was transcriptionally active whereas the nontranslocated gene was transcriptionally silent. We conclude that LYL1 has the properties of a lineage- and differentiation-specific HLH protein that contributes to T-cell neoplasia through its deregulated expression following chromosomal translocation.


Assuntos
Mapeamento Cromossômico , Expressão Gênica , Genes/genética , Fatores de Transcrição , Sequência de Aminoácidos , Animais , Sequência de Bases , Fatores de Transcrição Hélice-Alça-Hélice Básicos , Northern Blotting , Linhagem Celular , Cromossomos Humanos Par 19 , Proteínas de Ligação a DNA/genética , Humanos , Camundongos , Camundongos Endogâmicos BALB C , Dados de Sequência Molecular , Proteínas de Neoplasias/genética , Homologia de Sequência do Ácido Nucleico , Linfócitos T/citologia , Fatores de Transcrição TCF , Proteína 1 Semelhante ao Fator 7 de Transcrição
13.
IEEE Trans Med Imaging ; 10(4): 593-601, 1991.
Artigo em Inglês | MEDLINE | ID: mdl-18222865

RESUMO

The row action projection (RAP) method is used to increase the spatial resolution of images reconstructed via the filtered back projection (FBP) algorithm. An implementation of RAP is introduced which is computationally efficient and facilitates local adaptation of the projection operators. The local mean value as well as minimum and maximum bounds are used as constraints. The method is proposed to provide zoom-in capability, which yields a high-resolution estimate of a specified region of the image. Computer simulations demonstrate the new method to be very effective in recovering high-order spectral components of designated regions of the reconstructed image.

14.
Anal Biochem ; 177(1): 165-7, 1989 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-2662815

RESUMO

In order to determine whether an ampicillin resistance gene in a chimeric plasmid is active in transformed yeast cells, it is necessary to have a simple and quick assay procedure. We describe here a procedure for achieving this goal using an iodometric color reaction. This method is based on the fact that the ampicillin resistance gene product, beta-lactamase, can hydrolyze penicillin G and release a reducing product, which can be visualized by the discoloration of a dark blue iodine-starch complex. We have improved this method so that the assay can be carried out on agar plate and in liquid culture. It permits the detection of the beta-lactamase enzyme activity in yeast liquid culture at a concentration as low as 1 X 10(5) cells/ml within 12 h. This method is especially useful for certain yeast transformation systems, such as industrial yeast cultures, where the transformants can be selected only by drug resistance.


Assuntos
Resistência a Ampicilina/genética , Iodo , Saccharomyces cerevisiae/enzimologia , beta-Lactamases/análise , Colorimetria , Plasmídeos , Saccharomyces cerevisiae/genética , Amido , Transformação Genética
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...