Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 37
Filtrar
Filtros adicionais











Intervalo de ano
1.
Estud. pesqui. psicol. (Impr.) ; 18(4): 1175-1194, out.-dez. 2019.
Artigo em Português | LILACS, Index Psicologia - Periódicos técnico-científicos | ID: biblio-994982

RESUMO

Este artigo se propõe a analisar a situação da psicanálise nos cursos de psicologia das universidades do Rio de Janeiro, estabelecendo uma comparação com o caso de Buenos Aires. Para tal fim, utiliza um método de análise que implica construção documental, entrevistas e estudo teórico sobre a história e a atualidade da psicologia e da psicanálise nessas cidades. Entende-se que, além da chamada "crise" da psicanálise, ela mantém uma posição predominante nesses cursos. Espera-se que este trabalho contribua para uma discussão contextualizada dos cursos de psicologia em suas revisões curriculares.(AU)


We aim to analyse the situation of psychoanalysis in psychology undergraduate courses from universities of Rio de Janeiro, comparing these with the ones from Buenos Aires. For that purpose, we use a method of analysis that involves documental construction, interviews and theoretical study on the past history and the present reality of psychology and psychoanalysis in those cities. We understand that, besides the so-called "crisis" of psychoanalysis, this theoretical orientation maintains a predominant position in those courses. We expect that this work contributes to a contextualized discussion of psychology undergraduate courses and their curricular revisions.(AU)


Se propone analizar la situación del psicoanálisis en las carreras de psicología de universidades de Rio de Janeiro, estableciendo una comparación con el caso de Buenos Aires. Para tal fin, se utiliza un método de análisis que implica construcción documental, entrevista y estudio teórico, sobre la historia y actualidad de la psicología y el psicoanálisis en esas ciudades. Se entiende que, más allá de la llamada "crisis" del psicoanálisis, éste mantiene una posición predominante en esos cursos. Se espera que este trabajo contribuya a una discusión contextualizada de las carreras de Psicología y sus revisiones curriculares.(AU)


Assuntos
Humanos , Psicanálise , Psicologia , Argentina , Universidades , Brasil
2.
Anal Chim Acta ; 1081: 72-80, 2019 Nov 12.
Artigo em Inglês | MEDLINE | ID: mdl-31446967

RESUMO

A new calibration method based on the use of headspace solid-phase microextraction (HS-SPME) and in-fiber internal standardization, combined with gas chromatography coupled to mass spectrometry (GC/MS) was developed for quantifying Se volatile organic species released by plants exposed to chitosan-modified selenium nanoparticles (Cs-SeNPs). The effect of several parameters affecting extraction and separation of the selected organic species of selenium (dimethylselenium (DMSe), diethylselenium (DESe) and dimethyldiselenium (DMDSe)) and deuterated dimethyl sulphide (d6-DMS) employed as internal standard were studied and optimized using an experimental design. The developed methodology was applied for quantifying the volatile selenium compounds produced over time by the plant species Raphanus sativus and Brassica juncea grown in hydroponic solution containing 5 mg Se L-1 in the form Cs-SeNPs. The procedure employed consisted in two steps. Volatile selenium species released from the plants were first extracted in the SPME fiber located at the headspace of a box with a fixed volume. Subsequently, the internal standard placed in a vial subjected to the same conditions as plants was extracted on the same fiber than the one previously used for extracting selenium compounds. Finally the extracted compounds were separated and analyzed by GC/MS. Results evidenced Cs-SeNPs biotransformation into DMSe and DMDSe by both plants species during growing stage, in amounts of the order of ng. Additionally, the resulting data were submitted to multifactorial ANOVA to evaluate the influence of plant type and time of exposure to Cs-SeNPs on the production of volatile selenium compounds.

3.
Waste Manag ; 96: 15-24, 2019 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-31376959

RESUMO

A solid-liquid extraction method using ethanol-water mixtures was combined with cLC-DAD, LC-MS/MS and chemometric analyses for establishing the optimum extraction conditions of valuable polyphenols from spent coffee grounds. Chlorogenic and p-coumaric acids were the most abundant polyphenols found, ranging from 0.02 to 4.8 mg g-1 and 0.173-0.50 mg g-1, respectively. In addition, total polyphenol content (9-29 mg GAE g-1 DW), total flavonoid content (11-27 mg QE g-1 DW), total antioxidant activity (0.3-7 mg GAE g-1 DW) and free radical scavenging ability (DPPH assay, 64-927 µg extract g-1 at EC50) of obtained extracts were determined. Response surface methodology allowed obtaining predictive models for the extraction of each individual polyphenol. On the other hand, multifactorial ANOVA was used to establish differences between coffee and spent coffee ground extracts. Principal component analysis was also employed to relate antioxidant activities, total polyphenol and total flavonoid contents with both the polyphenols extracted and the residue coffee type. The overall results suggested that spent coffee grounds could be reused as a promising, inexpensive and natural source of bioactive polyphenols with potential industrial applications, thus minimizing the waste disposal and environmental impact.


Assuntos
Café , Polifenóis , Antioxidantes , Cromatografia Líquida , Espectrometria de Massas em Tandem
4.
Food Chem ; 295: 289-299, 2019 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-31174761

RESUMO

A method combining solid-liquid extraction based on ethanolic aqueous solution, cLC-DAD and chemometrics, was performed to extract and quantify polyphenols from citrus peels. LC-MS/MS was also employed for chemical profiling. The effect of extraction variables on the recovery was examined by experimental factorial design. Data were evaluated using multifactorial-ANOVA, response surface analysis and Principal Component Analysis. trans-Ferulic and p-coumaric antioxidants were found in lower quantities (<1.4 mg·g-1) in all peel extracts. Narangin flavonoid was also identified in all samples, while rutin flavonol was determined in the concentration range of 3.3-4.7 mg·g-1. The most abundant polyphenol in the extracts obtained from all evaluated citrus samples was the flavanone hesperidin (280-673 mg·g-1). Furthermore, peel extracts were evaluated in terms of total polyphenol and flavonoid content, total antioxidant activity and DPPH free radical scavenging. The obtained results suggested that evaluated citrus peel by-products could be reused as a source of polyphenols and transformed into value-added products.


Assuntos
Citrus/química , Polifenóis/análise , Polifenóis/isolamento & purificação , Resíduos/análise , Análise de Variância , Antioxidantes/análise , Antioxidantes/isolamento & purificação , Cromatografia Líquida , Flavonoides/análise , Flavonoides/isolamento & purificação , Hesperidina/análise , Hesperidina/isolamento & purificação , Extratos Vegetais/análise , Extratos Vegetais/química , Análise de Componente Principal , Espectrometria de Massas em Tandem
5.
J Chromatogr A ; 1601: 255-265, 2019 Sep 13.
Artigo em Inglês | MEDLINE | ID: mdl-31103200

RESUMO

A simple and efficient low-cost matrix solid-phase dispersion (MSPD) extraction based on TiO2 nanoparticles (NPs) and diatomaceous earth has been developed for the recovery of phenolic compounds from residual brewing yeast. Experimental conditions for MSPD extraction were optimized by an experimental design approach. A screening factorial design plus replicates at the center point, followed by surface response analysis were used. The simultaneous identification and quantification of eleven main natural polyphenols: caffeic, chlorogenic, p-coumaric, 3,4-dihydroxibenzoic, trans-ferulic and gallic acids, kaempferol, myricetin, naringin, quercetin and rutin, was possible by combining MSPD and capillary liquid chromatography couple to a diode array detection system (cLC-DAD) and liquid chromatography couple to a triple quadrupole analyzer (LC-MS/MS). Moreover, residual brewing yeast extracts were evaluated in terms of DPPH (1,1-diphenyl-2 picrylhydrazyl) free radical scavenging activity. Polyphenol-nanoparticle interaction was studied by UV-vis spectroscopy and electron transmission microscopy (TEM), pointing out a stable interplay that assists phenolic isolation. The extracted polyphenol quantities were within the 3.2-1,500 µg g-1 range, and the high antioxidant activity estimated suggested that developed MSPD is a successful, simple, efficient and rapid method for the extraction and recovery of bioactive phenolic compounds, which promotes the reuse and re-evaluation of brewing yeast agri-food by-products.


Assuntos
Técnicas de Química Analítica/métodos , Nanopartículas/química , Fenóis/análise , Saccharomyces cerevisiae/química , Extração em Fase Sólida , Titânio/química , Antioxidantes/química , Cromatografia Líquida de Alta Pressão , Cromatografia Líquida , Terra de Diatomáceas/química , Fenóis/isolamento & purificação , Polifenóis/análise , Polifenóis/química , Quercetina/análise , Espectrometria de Massas em Tandem
6.
J Environ Manage ; 242: 171-177, 2019 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-31035179

RESUMO

The immobilization of Candida rugosa lipase (CRL) onto biochar was studied in a series of batch experiments. CRL sorption behavior was evaluated as a function of pH, enzyme concentration, temperature and ionic strength. As the immobilized lipase was used for the catalytic esterification of oleic acid, its resistance to solvents and thermal stability were evaluated. CRL adsorption increased by increasing temperature, and with higher pH, reaching a maximum at pH 7.0. Immobilization increased lipase stability at 40 °C by more than 80% when compared to the free enzyme. Moreover, immobilized CRL showed high stability in the presence of tert-butanol, which prevents premature deactivation of the enzyme caused by alcohols during the reaction. Immobilization of CRL increased the oleic acid conversion rate. Our results suggest that biochar is a highly promising material for the immobilization of CRL lipase for the catalytic production of esters.

7.
Talanta ; 188: 393-403, 2018 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-30029393

RESUMO

The combination of UV-vis spectrophotometry with a chemometric calibration tool based on partial least squares (PLS) has allowed us the development of a multivariate analytical method that simultaneously estimates the concentration and size of mixtures of silver nanoparticles (AgNPs) in environmental water samples. The method is based on changes in the surface plasmon resonance band (SPRB) of AgNPs when they form aggregated/assembled structures with L-cysteine (L-cys). Measurementts were performed by employed a fixed-time kinetics method that implies that the final spectra (response) are obtained by subtstracting the solutions spectra at fixed times. Optimization of experimental conditions affecting aggregation such as time, temperature, pH and concentration of aggregating substance was performed by experimental design and response surface methodologies (RSM). A multivariate calibration model using AgNPs of known diameter size ((20 ±â€¯3), (41 ±â€¯3), (59 ±â€¯5) and (79 ±â€¯7) nm) within a concentration range between 0.62 and 2.5 mg L-1 was constructed by using a mixture experimental design and PLS. The method was finally applied to estimate size and concentration of AgNPs in AgNPs-spiked river and tap water samples. Water samples were spiked with individual, binary and ternary mixtures of AgNPs of different sizes and by using two types of AgNPs: citrate-coated AgNPs (cit-AgNPs) and polyvinylpyrrolidone-coated AgNPs (PVP-AgNPs). A good correspondence was obtained between predicted values and the total amount of AgNPs added with recovery values ranged within 80-160% for the individual mixtures, 68-108% for the binary mixtures and 60-64% for the ternary mixtures of AgNPs. Finally, transmission electron microscopy (TEM) measurements were performed for those cases where discrepancies between the expected and the obtained values were observed. TEM micrographs evidenced the presence of agglomerates or aggregates of AgNPs in some of the mixtures or water tested.

8.
Food Chem ; 267: 246-254, 2018 Nov 30.
Artigo em Inglês | MEDLINE | ID: mdl-29934164

RESUMO

A method combining aqueous extraction, reversed-phase high-performance capillary liquid chromatography with photodiode array detection (cLC-DAD) and chemometric tools, was developed to determine phenolic compounds in residual brewing yeast. The effect of temperature, nature of extraction solvent and method for separation of extract solution were studied to optimize the extraction conditions on the basis of total phenolic content (TPC), total flavonoids content (TFC) and antioxidant capacity. Polyphenols were determined by cLC-DAD. Flavonols as rutin and kaempferol, flavonoids as naringin, phenolic acids as gallic acid and antioxidants as trans-ferulic and p-coumaric acids were found and quantified in the brewing residue. Data were subjected to evaluation using multifactor ANOVA and principal component analysis (PCA), both showing that lyophilization pretreatment affects the content of individual polyphenols and that residual brewing yeast contains higher polyphenol amounts than the liquid beer waste. The obtained results suggest that residual brewing yeast could be a source of polyphenols.


Assuntos
Cromatografia Líquida de Alta Pressão , Polifenóis/análise , Saccharomyces cerevisiae/metabolismo , Antioxidantes/química , Cromatografia de Fase Reversa , Flavonoides/análise , Flavonoides/química , Umidade , Concentração de Íons de Hidrogênio , Polifenóis/química , Análise de Componente Principal , Saccharomyces cerevisiae/crescimento & desenvolvimento
9.
Sci Total Environ ; 616-617: 960-969, 2018 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-29096960

RESUMO

Biochar (BC) is gaining attention as a soil amendment that can remediate metal polluted soils. The simultaneous effects of BC on copper (Cu) mobility, microbial activities in soil using metallophytes have scarcely been addressed. The objective of this study was to evaluate the effects of biochar BCs on Cu immobilization and over soil microbial communities in a Cu-contaminated soil evaluated over a two-year trial. A Cu-contaminated soil (338mgkg-1) was incubated with chicken manure biochar (CMB) or oat hull biochar (OHB) at rates of 1 and 5% w/w. Metallophyte Oenothera picensis was grown over one season (six months). The above process was repeated for 3 more consecutive seasons using the same soils. The BCs increased the soil pH and decreased the Cu exchangeable fraction Cu by 5 and 10 times (for OHB and CMB, respectively) by increasing the Cu bound in organic matter and residual fractions, and its effects were consistent across all seasons evaluated. BCs provided favorable habitat for microorganisms that was evident in increased microbial activity. The DHA activity was increased in all BC treatments, reaching a maximum of 7 and 6 times higher than control soils in CMB and OHB. Similar results were observed in microbial respiration, which increased 53% in OHB and 61% in CMB with respect to control. The BCs produced changes in microbial communities in all seasons evaluated. The fungal and bacterial richness were increased by CMB and OHB treatments; however, no clear effects were observed in the microbial diversity estimators. The physiochemical and microbiological effects produced by BC result in an increase of plant biomass production, which was on average 3 times higher than control treatments. However, despite being a metallophyte, O. picensis did not uptake Cu efficiently. Root and shoot Cu concentrations decreased or changed insignificantly in most BC treatments.


Assuntos
Carvão Vegetal/química , Cobre/análise , Microbiologia do Solo , Poluentes do Solo/análise , Solo/química , Bactérias/metabolismo , Cobre/química , Poluição Ambiental/estatística & dados numéricos , Fungos/metabolismo , Poluentes do Solo/química
10.
Environ Sci Pollut Res Int ; 24(16): 14104-14116, 2017 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-28417325

RESUMO

We characterized humic substances (HS) extracted from a Cu-contaminated soil without compost addition (C) or amended with a wheat straw-based compost (WSC) (H1), co-composted with Fe2O3 (H2), or co-composted with an allophane-rich soil (H3). Extracted HS were characterized under electron microscopy (SEM/TEM), energy-dispersive X-ray (X-EDS), and Fourier transform infrared (FTIR) spectroscopy. In addition, HS extracted from WSC (H4) were characterized at pH 4.0 and 8.0 with descriptive purposes. At pH 4.0, globular structures of H4 were observed, some of them aggregating within a large network. Contrariwise, at pH 8.0, long tubular and disaggregated structures prevailed. TEM microscopy suggests organo-mineral interactions at scales of 1 to 200 nm with iron oxide nanoparticles. HS extracted from soil-compost incubations showed interactions at nanoscale with minerals and crystal compounds into the organic matrix of HS. Bands associated to acidic functional groups of HS may suggest potential sorption interactions with transition metals. We conclude that metal ions and pH have an important role controlling the morphology and configuration of HS from WSC. Characterization of H4 extracted from WSC showed that physicochemical protection of HS could be present in composting systems treated with inorganic materials. Finally, the humified fractions obtained from compost-amended soils may have an important effect on metal-retention, supporting their potential use in metal-contaminated soils.


Assuntos
Cobre/química , Substâncias Húmicas , Poluentes do Solo/química , Compostagem , Compostos Férricos , Solo
11.
Int J Mol Sci ; 18(1)2017 Jan 10.
Artigo em Inglês | MEDLINE | ID: mdl-28075409

RESUMO

The human immunodeficiency virus type 1 (HIV-1) Vpr protein is an attractive target for antiretroviral drug development. The conservation both of the structure along virus evolution and the amino acid sequence in viral isolates from patients underlines the importance of Vpr for the establishment and progression of HIV-1 disease. While its contribution to virus replication in dividing and non-dividing cells and to the pathogenesis of HIV-1 in many different cell types, both extracellular and intracellular forms, have been extensively studied, its precise mechanism of action nevertheless remains enigmatic. The present review discusses how the apparently multifaceted interplay between Vpr and host cells may be due to the impairment of basic metabolic pathways. Vpr protein modifies host cell energy metabolism, oxidative status, and proteasome function, all of which are likely conditioned by the concentration and multimerization of the protein. The characterization of Vpr domains along with new laboratory tools for the assessment of their function has become increasingly relevant in recent years. With these advances, it is conceivable that drug discovery efforts involving Vpr-targeted antiretrovirals will experience substantial growth in the coming years.


Assuntos
Fármacos Anti-HIV/farmacologia , Infecções por HIV/etiologia , HIV-1/efeitos dos fármacos , Produtos do Gene vpr do Vírus da Imunodeficiência Humana/antagonistas & inibidores , Animais , Fármacos Anti-HIV/uso terapêutico , Proteínas de Transporte/metabolismo , Sequência Conservada , Progressão da Doença , Descoberta de Drogas , Evolução Molecular , Infecções por HIV/tratamento farmacológico , Infecções por HIV/metabolismo , HIV-1/fisiologia , Humanos , Lentivirus de Primatas/genética , Ligação Proteica , Replicação Viral , Produtos do Gene vpr do Vírus da Imunodeficiência Humana/química , Produtos do Gene vpr do Vírus da Imunodeficiência Humana/metabolismo
12.
Virus Res ; 213: 116-123, 2016 Feb 02.
Artigo em Inglês | MEDLINE | ID: mdl-26597719

RESUMO

The human immunodeficiency virus type 1 (HIV-1) encodes for accessory viral protein R (Vpr), which arrests the cell cycle of host cells at G2 and causes mitochondrial dysfunction and alterations in glycolysis. High-level expression of Vpr protein correlates with increased viral production and disease progression. Vpr causes structural and functional injury in many types of eukaryotic cells, whether or not they are permissive for viral replication; among them is the budding yeast Saccharomyces cerevisiae. We hypothesized that the dramatic Vpr-induced injuries in yeast could be prevented by strengthening their redox response capacity. We show that exogenous addition of glutathione (GSH) or its prodrug, N-acetylcysteine (NAC), protected budding yeasts from Vpr-induced cytopathic effects. Moreover, addition of adenosine triphosphate (ATP) to growing cultures of Vpr-producing yeast returned cellular growth to control levels, whereas the addition dehydroascorbic acid (DHA) had only a minor protective effect. The diminished protein levels of Cox2p and Cox4p in wild typeVpr-producing yeasts together with the acute sensitivity of petite yeasts to Vpr activity may have been caused by low intracellular ATP levels. As a consequence of this energy deficit, eukaryotic cells would be unable to synthetize adequate supplies of GSH or to signal the mitochondrial retrograde response. Our findings strongly suggest that the cytopathogenic effect of Vpr protein in eukaryotic cells can be prevented by increasing intracellular antioxidant stores or, alternatively, supplying external ATP. Furthermore, these results support a potentially promising future for S. cerevisiae expression as a modality to search for Vpr-targeted inhibitors.


Assuntos
Glutationa/metabolismo , Estresse Oxidativo , Saccharomycetales/fisiologia , Produtos do Gene vpr do Vírus da Imunodeficiência Humana/metabolismo , Trifosfato de Adenosina/metabolismo , Saccharomycetales/genética , Saccharomycetales/crescimento & desenvolvimento
13.
Cell Tissue Bank ; 17(1): 137-45, 2016 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-26220398

RESUMO

Mobilized peripheral blood (MPB) bone marrow cells possess the potential to differentiate into a variety of mesenchymal tissue types and offer a source of easy access for obtaining stem cells for the development of experimental models with applications in tissue engineering. In the present work, we aimed to isolate by magnetic activated cell sorting CD90+ cells from MPB by means of the administration of Granulocyte-Colony Stimulating Factor and to evaluate cell proliferation capacity, after thawing of the in vitro culture of this population of mesenchymal stem cells (MSCs) in sheep. We obtained a median of 8.2 ± 0.6 million of CD90+ cells from the 20-mL MPB sample. After thawing, at day 15 under in vitro culture, the mean CD90+ cells determined by flow cytometry was 92.92 ± 1.29 % and cell duplication time determined by crystal violet staining was 47.59 h. This study describes for the first time the isolation, characterization, and post-in vitro culture thawing of CD90+ MSCs from mobilized peripheral blood in sheep. This population can be considered as a source of MSCs for experimental models in tissue engineering research.


Assuntos
Criopreservação/métodos , Células-Tronco Mesenquimais/citologia , Células-Tronco de Sangue Periférico/citologia , Antígenos Thy-1/metabolismo , Animais , Diferenciação Celular , Proliferação de Células , Separação Celular , Forma Celular , Citometria de Fluxo , Imunofluorescência , Imunofenotipagem , Masculino , Ovinos
14.
Viruses ; 7(8): 4352-68, 2015 Aug 04.
Artigo em Inglês | MEDLINE | ID: mdl-26247957

RESUMO

Viral protein U (Vpu) is a lentiviral viroporin encoded by human immunodeficiency virus type 1 (HIV-1) and some simian immunodeficiency virus (SIV) strains. This small protein of 81 amino acids contains a single transmembrane domain that allows for supramolecular organization via homoligomerization or interaction with other proteins. The topology and trafficking of Vpu through subcellular compartments result in pleiotropic effects in host cells. Notwithstanding the high variability of its amino acid sequence, the functionality of Vpu is well conserved in pandemic virus isolates. This review outlines our current knowledge on the interactions of Vpu with the host cell. The regulation of cellular physiology by Vpu and the validity of this viroporin as a therapeutic target are also discussed.


Assuntos
Antígenos CD4/biossíntese , HIV-1/fisiologia , Interações Hospedeiro-Patógeno , Proteínas do Vírus da Imunodeficiência Humana/metabolismo , Multimerização Proteica , Proteínas Virais Reguladoras e Acessórias/metabolismo , Liberação de Vírus , Regulação para Baixo , Humanos , Ligação Proteica , Transporte Proteico
15.
Biomed Chromatogr ; 28(1): 59-83, 2014 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-23982862

RESUMO

Separation of enantiomers remains a challenge owing to their identical physical and chemical properties in an achiral environment, and research on specialized separation techniques such as multidimensional achiral-chiral liquid chromatography continues to resolve individual enantiomers in complex samples. Recent advances in application of multidimensional liquid chromatography applied to chiral analysis are reviewed. For this reason, benefits of achiral-chiral coupling are shown, with emphasis in applications on biological and pharmaceutical fields as well as pesticide analysis. A description of standard instrumental setup in both heart-cut and comprehensive multidimensional liquid chromatography is shown. The most broadly used chiral stationary phases for multidimensional liquid chromatography are summarized. An extensive overview of different interface designs applied to complex samples is presented.


Assuntos
Cromatografia Líquida/métodos , Praguicidas/isolamento & purificação , Preparações Farmacêuticas/isolamento & purificação , Cromatografia Líquida/instrumentação , Praguicidas/química , Preparações Farmacêuticas/química , Estereoisomerismo
16.
Biomed Chromatogr ; 27(11): 1413-22, 2013 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-23703259

RESUMO

A direct chiral LC-UV method was optimized for the determination of salbutamol (SAL) ß2 -agonist in environmental water. Two commercially available columns were evaluated: teicoplanin Chirobiotic-T™ (150 × 2.1 mm i.d., 5 µm) and vancomycin Chirobiotic-V™ (150 × 2.1 mm i.d., 5 µm). Finally, teicoplanin chiral stationary phase was selected for SAL enantiomer resolution. In order to preserve its integrity and maintain the column performance for longer time, the use of additives such as triethylamine (TEA) in the mobile phase was avoided. Experimental design was applied to simultaneously evaluate the influence of several parameters involved in enantiomer separation and to establish the conditions for acceptable resolution and performance in short analysis time. Optimum mobile phase was methanol-20 mM ammonium acetate buffer at pH 4.5 (98:2, v/v). A solid-phase extraction procedure for sample pre-concentration and clean-up allowed the determination of chiral SAL residues in natural water samples spiked at low concentrations in the range 1.0-20 ng mL(-1) . Reproducible recoveries, between 77 and 98%, were obtained and matrix effect was negligible. Injection of sample solutions at low elution strength permitted the SAL enantioresolution in the natural water complex matrix with satisfactory sensitivity and precision.


Assuntos
Agonistas de Receptores Adrenérgicos beta 2/análise , Albuterol/análise , Cromatografia Líquida de Alta Pressão/métodos , Cromatografia de Fase Reversa/métodos , Água Doce/análise , Teicoplanina/química , Poluentes Químicos da Água/análise , Limite de Detecção , Estereoisomerismo
17.
Biochemistry ; 52(1): 171-7, 2013 Jan 08.
Artigo em Inglês | MEDLINE | ID: mdl-23240720

RESUMO

Human immunodeficiency virus type 1 (HIV-1) Vpu is an integral membrane protein that belongs to the viroporin family. Viroporins interact with cell membranes, triggering membrane permeabilization and promoting release of viral particles. In vitro electrophysiological methods have revealed changes in membrane ion currents when Vpu is present; however, in vivo the molecular mechanism of Vpu at the plasma membrane is still uncertain. We used the yeast Saccharomyces cerevisiae as a genetic model system to analyze how Vpu ion channel impacts cellular homeostasis. Inducible expression of Vpu impaired cell growth, suggesting that this viral protein is toxic to yeast cultures. This toxicity decreased with extracellular acidic pH. Also, Vpu toxicity diminished as the extracellular K(+) concentration was increased. However, expression of the Vpu protein suppresses the growth defect of K(+) uptake-deficient yeast (Δtrk1,2). The phenotype rescue of these highly hyperpolarized cells was almost total when they were grown in medium supplemented with high concentrations of KCl (100 mM) at pH 7.0 but was significantly reduced when the extracellular K(+) concentration or pH was decreased. These results indicate that Vpu has the ability to modify K(+) transport in both yeast strains. Here, we show also that Vpu confers tolerance to the aminoglycoside antibiotic hygromycin B in Δtrk1,2 yeast. Our results suggest that Vpu interferes with cell growth of wild-type yeast but improves proliferation of the hyperpolarized trk1,2 mutant by inducing plasma membrane depolarization. Furthermore, evaluation of the ion channel activity of the Vpu protein in Δtrk1,2 yeast could aid in the development of a high-throughput screening assay for molecules that target the retroviral protein.


Assuntos
HIV-1/fisiologia , Interações Hospedeiro-Patógeno , Proteínas do Vírus da Imunodeficiência Humana/metabolismo , Potássio/metabolismo , Saccharomyces cerevisiae/virologia , Proteínas Virais Reguladoras e Acessórias/metabolismo , Transporte Biológico , Expressão Gênica , Infecções por HIV/metabolismo , Infecções por HIV/virologia , Proteínas do Vírus da Imunodeficiência Humana/genética , Humanos , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/metabolismo , Proteínas Virais Reguladoras e Acessórias/genética
18.
Crit Care ; 15(4): R201, 2011 Aug 17.
Artigo em Inglês | MEDLINE | ID: mdl-21849039

RESUMO

INTRODUCTION: Most cases of the 2009 influenza A (H1N1) infection are self-limited, but occasionally the disease evolves to a severe condition needing hospitalization. Here we describe the evolution of the respiratory compromise, ventilatory management and laboratory variables of patients with diffuse viral pneumonitis caused by pandemic 2009 influenza A (H1N1) admitted to the ICU. METHOD: This was a multicenter, prospective inception cohort study including adult patients with acute respiratory failure requiring mechanical ventilation (MV) admitted to 20 ICUs in Argentina between June and September of 2009 during the influenza A (H1N1) pandemic. In a standard case-report form, we collected epidemiological characteristics, results of real-time reverse-transcriptase--polymerase-chain-reaction viral diagnostic tests, oxygenation variables, acid-base status, respiratory mechanics, ventilation management and laboratory tests. Variables were recorded on ICU admission and at days 3, 7 and 10. RESULTS: During the study period 178 patients with diffuse viral pneumonitis requiring MV were admitted. They were 44 ± 15 years of age, with Acute Physiology And Chronic Health Evaluation II (APACHE II) scores of 18 ± 7, and most frequent comorbidities were obesity (26%), previous respiratory disease (24%) and immunosuppression (16%). Non-invasive ventilation (NIV) was applied in 49 (28%) patients on admission, but 94% were later intubated.Acute respiratory distress syndrome (ARDS) was present throughout the entire ICU stay in the whole group (mean PaO2/FIO2 170 ± 25). Tidal-volumes used were 7.8 to 8.1 ml/kg (ideal body weight), plateau pressures always remained < 30 cmH2O, without differences between survivors and non-survivors; and mean positive end-expiratory pressure (PEEP) levels used were between 8 to 12 cm H2O. Rescue therapies, like recruitment maneuvers (8 to 35%), prone positioning (12 to 24%) and tracheal gas insufflation (3%) were frequently applied. At all time points, pH, platelet count, lactate dehydrogenase assay (LDH) and Sequential Organ Failure Assessment (SOFA) differed significantly between survivors and non-survivors. Lack of recovery of platelet count and persistence of leukocytosis were characteristic of non-survivors. Mortality was high (46%); and length of MV was 10 (6 to 17) days. CONCLUSIONS: These patients had severe, hypoxemic respiratory failure compatible with ARDS that persisted over time, frequently requiring rescue therapies to support oxygenation. NIV use is not warranted, given its high failure rate. Death and evolution to prolonged mechanical ventilation were common outcomes. Persistence of thrombocytopenia, acidosis and leukocytosis, and high LDH levels found in non-survivors during the course of the disease might be novel prognostic findings.


Assuntos
Vírus da Influenza A Subtipo H1N1/isolamento & purificação , Influenza Humana/epidemiologia , Influenza Humana/fisiopatologia , Pulmão/fisiopatologia , Insuficiência de Múltiplos Órgãos/epidemiologia , Pneumonia/virologia , Respiração Artificial , Adulto , Argentina/epidemiologia , Estudos de Coortes , Feminino , Mortalidade Hospitalar , Humanos , Influenza Humana/virologia , Unidades de Terapia Intensiva , Masculino , Pessoa de Meia-Idade , Insuficiência de Múltiplos Órgãos/fisiopatologia , Pneumonia/mortalidade , Pneumonia/fisiopatologia , Estudos Prospectivos , Reação em Cadeia da Polimerase em Tempo Real , Testes de Função Respiratória , Análise de Sobrevida
19.
Span J Psychol ; 14(1): 385-91, 2011 May.
Artigo em Inglês | MEDLINE | ID: mdl-21568195

RESUMO

The concept of prospective memory is relatively recent. Thus, it is necessary to have instruments to assess it, in interaction with retrospective memory. The Prospective and Retrospective Memory Questionnaire (PRMQ; Smith et al., 2000) is an instrument that has been effectively used for assessment in several languages. Nevertheless, there is still no Spanish adaptation. The aim of this study was to translate the PRMQ and obtain information about its psychometric properties. A back translation process was applied to the PRMQ. The resulting PRMQ-S was self-administered to 520 subjects after applying the pilot test. Confirmatory factor analysis (CFA) was used to test competing models of its latent structure. Internal consistency was evaluated using Cronbach's alpha. The results showed an adequate internal consistency of the total scale and the Prospective and Retrospective scales were: .89, .84 and .76, respectively. The factor structure was compared with the original study. Our results suggested a disagreement with the tripartite model defended by the authors of the PRMQ. Since there is a high correlation between two factors in the bi-factor model, and the tripartite model showed non-significant loadings to the two specific factors, we recommend that the PRMQ-S be used as one general memory score. We demonstrated adequate psychometric properties of the PRMQ-S if it is used as unique measurement of memory failures. These results are relevant due to the need for a short and accurate instrument in our language that explores memory failures, which has a major impact on the activities of daily living.


Assuntos
Comparação Transcultural , Intenção , Rememoração Mental , Testes Neuropsicológicos/estatística & dados numéricos , Adolescente , Adulto , Fatores Etários , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Psicometria/estatística & dados numéricos , Valores de Referência , Reprodutibilidade dos Testes , Tradução , Adulto Jovem
20.
Span. j. psychol ; 14(1): 385-391, mayo 2011. tab, ilus
Artigo em Inglês | IBECS | ID: ibc-96484

RESUMO

The concept of prospective memory is relatively recent. Thus, it is necessary to have instruments to assess it, in interaction with retrospective memory. The Prospective and Retrospective Memory Questionnaire (PRMQ; Smith et al., 2000) is an instrument that has been effectively used for assessment in several languages. Nevertheless, there is still no Spanish adaptation. The aim of this study was to translate the PRMQ and obtain information about its psychometric properties. A back translation process was applied to the PRMQ. The resulting PRMQ-S was self-administered to 520 subjects after applying the pilot test. Confirmatory factor analysis (CFA) was used to test competing models of its latent structure. Internal consistency was evaluated using Cronbach’s alpha. The results showed an adequate internal consistency of the total scale and the Prospective and Retrospective scales were: .89, .84 and .76, respectively. The factor structure was compared with the original study. Our results suggested a disagreement with the tripartite model defended by the authors of the PRMQ. Since there is a high correlation between two factors in the bi-factor model, and the tripartite model showed non-significant loadings to the two specific factors, we recommend that the PRMQ-S be used as one general memory score. We demonstrated adequate psychometric properties of the PRMQ-S if it is used as unique measurement of memory failures. These results are relevant due to the need for a short and accurate instrument in our language that explores memory failures, which has a major impact on the activities of daily living (AU)


El concepto de memoria prospectiva es relativamente reciente. Por lo que es necesario contar con instrumentos para evaluarla en interacción con la memoria retrospectiva. El Cuestionario de Memoria Prospectiva y retrospectiva (PRMQ; Smith et al., 2000) es un instrumento que ha sido eficientemente utilizado para evaluarlas, en varios idiomas. Sin embargo, no se detectó versión alguna en español de dicho cuestionario. El propósito de este estudio fue traducir el PRMQ y obtener información sobre sus propiedades psicométricas. Un proceso de traducción inversa fue aplicado al PRMQ, el resultante PRMQ-S se aplicó a 520 personas, después de una prueba piloto. Para los análisis se utilizó el Análisis Factorial Confirmatorio y el Alfa de Cronbach. Los resultados reflejaron adecuada consistencia interna de la escala completa y de las subescalas de memoria prospectiva y retrospectiva: .89, .84 y .76, respectivamente. La estructura factorial fue comparada con el estudio original. Nuestros resultados sugieren un desacuerdo con el modelo tripartito defendido por los autores del PRMQ. La fuerte correlación entre los dos factores en el modelo bifactorial y el modelo tripartito, que muestra pesos factoriales no significativos, dan la pauta para recomendar que el PRMQ-S sea utilizado como un puntaje general de memoria. Nuestros resultados demuestran adecuadas propiedades psicométricas al ser utilizado como una medida única de fallos en la memoria. Estos resultados son relevantes debido a la necesidad de un instrumento breve en español que evalúe los fallos en la memoria que afectan el desempeño en las actividades cotidianas (AU)


Assuntos
Humanos , Masculino , Feminino , Adolescente , Adulto , Pessoa de Meia-Idade , Idoso , Idoso de 80 Anos ou mais , Memória/fisiologia , Transtornos da Memória/psicologia , Psicometria/métodos , Doença de Alzheimer/epidemiologia , Doença de Alzheimer/psicologia , Inquéritos e Questionários , Psicometria/organização & administração , Psicometria/tendências , Análise Fatorial , Escalas de Graduação Psiquiátrica Breve/estatística & dados numéricos , Escalas de Graduação Psiquiátrica/estatística & dados numéricos
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA