Identificação de alguns constituintes químicos de Indigofera hirsuta Linn. (Fabaceae) por CLAE-IES-EM (TOF) e avaliação da atividade antirradicalar

A rapid analytical approach, suitable to characterize the compounds present in the aqueous and methanol extracts prepared from the aerial parts of Indigofera hirsute, was developed. The method based on high-performance liquid chromatography coupled to mass spectrometry, electrospray positive ionization and detection by time of flight (HPLC-ESI-MS-TOF) identified, tryptophan, uracil, rutin, kaempferol-3-O-β-D-glucopyranoside, gallic acid and methyl gallate. The antiradical activity of this extract was evaluated using DPPH assay, with gallic acid as antiradical pattern. The study revealed the antiradical activity of methyl galatte (EC50 = 5 ± 0.3 µg mL-1) galic acid (EC50 = 5 ± 0.2 µg mL-1) and rutin (EC50 = 21.6 ± 0.6 µg m L-1), isolated from methanol extract (EC50 = 67.7 ± 0.9 µg mL-1), which showed strong antiradical activity.

Comparative analysis of two-dimensional electrophoresis maps (2-DE) of Helicobacter pylori from Brazilian patients with chronic gastritis and duodenal ulcer: a preliminary report

Helicobacter pylori is a bacterium recognized as the major cause of peptic ulcer and chronic gastritis. Recently, a proteome-based approach was developed to investigate pathogenic factors related to H. pylori. In this preliminary study, H. pylori strains were isolated from gastric biopsies of patients with chronic gastritis and duodenal ulcers. A partial proteomic analysis of H. pylori strains was performed by bacterial lyses and proteins were separated by two-dimensional gel electrophoresis (2-DE). A comparative analysis was performed to verify a differential protein expression between these two 2-DE maps. These data should be useful to clarify the role of different proteins related to bacterial pathogenesis. This study will be completed using a larger number of samples and protein identification of H. pylori by MALDI-TOF mass spectrometry.

Candida albicans PROTEIN PROFILE CHANGES IN RESPONSE TO THE BUTANOLIC EXTRACT OF Sapindus saponariaL.

Candida albicans is an opportunistic human pathogen that is capable of causing superficial and systemic infections in immunocompromised patients. Extracts of Sapindus saponaria have been used as antimicrobial agents against various organisms. In the present study, we used a combination of two-dimensional polyacrylamide gel electrophoresis (2D-PAGE) and matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) to identify the changes in protein abundance of C. albicans after exposure to the minimal inhibitory concentration (MIC) and sub-minimal inhibitory concentration (sub-MIC) of the butanolic extract (BUTE) of S. saponaria and also to fluconazole. A total of six different proteins with greater than 1.5 fold induction or repression relative to the untreated control cells were identified among the three treatments. In general, proteins/enzymes involved with the glycolysis (GPM1, ENO1, FBA1), amino acid metabolism (ILV5, PDC11) and protein synthesis (ASC1) pathways were detected. In conclusion, our findings reveal antifungal-induced changes in protein abundance of C. albicans. By using the previously identified components of the BUTE of S. saponaria(e.g., saponins and sesquiterpene oligoglycosides), it will be possible to compare the behavior of compounds with unknown mechanisms of action, and this knowledge will help to focus the subsequent biochemical work aimed at defining the effects of these compounds.

On line pre-concentration for simultaneous determination of low molecular weight organic acids and inorganic anions in Amazonian river water samples employing ion chromatography with conductivity detection

An ion chromatography procedure, employing an IonPac AC15 concentrator column was used to investigate on line preconcentration for the simultaneous determination of inorganic anions and organic acids in river water. Twelve organic acids and nine inorganic anions were separated without any interference from other compounds and carry-over problems between samples. The injection loop was replaced by a Dionex AC15 concentrator column. The proposed procedure employed an auto-sampler that injected 1.5 ml of sample into a KOH mobile phase, generated by an Eluent Generator, at 1.5 mL min-1, which carried the sample to the chromatographic columns (one guard column, model AG-15, and one analytical column, model AS15, with 250 x 4mm i.d.). The gradient elution concentrations consisted of a 10.0 mmol l-1 KOH solution from 0 to 6.5 min, gradually increased to 45.0 mmol l-1 KOH at 21 min., and immediatelly returned and maintained at the initial concentrations until 24 min. of total run. The compounds were eluted and transported to an electro-conductivity detection cell that was attached to an electrochemical detector. The advantage of using concentrator column was the capability of performing routine simultaneous determinations for ions from 0.01 to 1.0 mg l-1 organic acids (acetate, propionic acid, formic acid, butyric acid, glycolic acid, pyruvate, tartaric acid, phthalic acid, methanesulfonic acid, valeric acid, maleic acid, oxalic acid, chlorate and citric acid) and 0.01 to 5.0 mg l-1 inorganic anions (fluoride, chloride, nitrite, nitrate, bromide, sulfate and phosphate), without extensive sample pretreatment and with an analysis time of only 24 minutes.

Bone tuberculosis in Roman Period Pannonia (western Hungary)

The purpose of this study was to analyse a skeleton (adult female, 25-30 years) that presented evidence of tuberculous spondylitis. The skeleton, dated from the Roman Period (III-VI centuries), was excavated near the town of Győr, in western Hungary. The skeleton was examined by gross observation supplemented with mycolic acid and proteomic analyses using MALDI-TOF/TOF tandem mass spectrometry. The biomolecular analyses supported the morphological diagnosis.

Polyphasic characterisation of Burkholderia cepaciacomplex species isolated from children with cystic fibrosis

Cystic fibrosis (CF) patients with Burkholderia cepacia complex (Bcc) pulmonary infections have high morbidity and mortality. The aim of this study was to compare different methods for identification of Bcc species isolated from paediatric CF patients. Oropharyngeal swabs from children with CF were used to obtain isolates of Bcc samples to evaluate six different tests for strain identification. Conventional (CPT) and automatised (APT) phenotypic tests, polymerase chain reaction (PCR)-recA, restriction fragment length polymorphism-recA, recAsequencing, and matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) were applied. Bacterial isolates were also tested for antimicrobial susceptibility. PCR-recA analysis showed that 36 out of the 54 isolates were Bcc. Kappa index data indicated almost perfect agreement between CPT and APT, CPT and PCR-recA, and APT and PCR-recA to identify Bcc, and MALDI-TOF and recAsequencing to identify Bcc species. The recAsequencing data and the MALDI-TOF data agreed in 97.2% of the isolates. Based on recA sequencing, the most common species identified were Burkholderia cenocepacia IIIA (33.4%),Burkholderia vietnamiensis (30.6%), B. cenocepaciaIIIB (27.8%), Burkholderia multivorans (5.5%), and B. cepacia (2.7%). MALDI-TOF proved to be a useful tool for identification of Bcc species obtained from CF patients, although it was not able to identify B. cenocepacia subtypes.

Angiografia por ressonância magnética: aspectos técnicos de um método de estudo vascular não-invasivo

As primeiras técnicas de angiografia por ressonância magnética (angio-RM) utilizavam seqüências sensíveis ao fluxo sanguíneo para estabelecimento do contraste vascular. Há três técnicas fundamentadas neste princípio: contraste de fase ("phase-contrast"), TOF ("time-of-flight") e as técnicas de sangue escuro ("black blood"). Estas seqüências, de aquisição demorada, são mais suscetíveis a artefatos de movimento, perda de sinal em áreas de estenoses ou turbilhonamento de fluxo, e apresentam ainda baixa sensibilidade à detecção do fluxo lento. O uso do contraste paramagnético para estudos angiográficos pela ressonância magnética ofereceu um método simples, rápido e de excelente detalhamento vascular, baseando o contraste da imagem no realce do sinal vascular em oposição à supressão dos demais tecidos. Metodologias modernas que priorizam a obtenção do espaço k central, responsável pelo contraste da imagem, e o aperfeiçoamento das técnicas de planejamento do intervalo temporal para aquisição dos dados foram fatores fundamentais para o aprimoramento técnico da angio-RM. O papel atual da angio-RM como ferramenta diagnóstica merece destaque na avaliação de anomalias anatômicas, estenoses, oclusões e complicações vasculares pós-cirúrgicas, principalmente nos casos de transplantes de órgãos. Suas principais vantagens estão na não utilização do contraste iodado ou radiação ionizante, rapidez e fácil execução, mínima invasividade e possibilidade de avaliar complementarmente o parênquima de órgãos adjacentes de interesse diagnóstico.

Angiorressonância magnética do crânio: revisão de 100 casos

Neste trabalho foram analisados, retrospectivamente, os exames de 100 pacientes que se submeteram a angiografia por ressonância magnética (angio-RM) do crânio com diferentes indicações clínicas. Os objetivos deste trabalho foram discutir as vantagens e desvantagens da técnica 3D TOF em exames de angio-RM cerebral e verificar as principais indicações de angio-RM na avaliação das lesões vasculares intracranianas e a freqüência dos principais achados nestes exames. As principais indicações para a realização de angio-RM neste trabalho foram cefaléia (n = 29), acidente vascular encefálico (n = 14) e ataque isquêmico transitório (n = 11). Em 11 casos não havia indicação clínica e os demais tiveram indicações diversas. Cinqüenta e dois por cento dos exames apresentaram alguma alteração. Os principais achados foram estenose vascular (n = 30), aneurisma (n = 10), variações anatômicas (n = 6), malformações vasculares (n = 4) e trombose dos seios durais (n = 2). A técnica 3D TOF, única utilizada neste trabalho, mostrou-se eficiente na maioria dos casos, com um tempo relativamente curto para sua aquisição. Como desvantagem, não se mostra eficaz para cobrir grandes volumes.

Avaliação da aterosclerose carotídea por intermédio de ultra-sonografia e ressonância magnética

OBJETIVO: Identificar ateromas carotídeos em coronariopatas com indicação de terapia cirúrgica. Avaliar o grau de estenose das artérias carótidas internas por meio de ultra-sonografia com Doppler colorido (UDC) e angiografia por ressonância magnética (ARM). Comparar a ecogenicidade das placas visualizadas pela ultra-sonografia (US), com a intensidade de sinal nos exames de ressonância magnética (RM). Avaliar a qualidade de imagens e confiabilidade interobservadores nos exames de RM. MATERIAIS E MÉTODOS: Estudo prospectivo em 50 pacientes. Utilizamos US e RM em seqüências ponderadas em T1 e T2, ambas pelas técnicas "black-blood" (BB) e "fat sat black-blood" (FSBB), e ARM 3D TOF ("time-of-flight'') com e sem contraste paramagnético. RESULTADOS: Do total de 100 segmentos, 81% apresentaram estenose pela US. Em 72 placas com ecogenicidade tipo 4 houve aumento da intensidade de sinal em 59,7% em T1-BB, 65,3% em T1-FSBB, 62,5% em T2-BB e 66,7% em T2-FSBB. Nas placas tipo 2 houve aumento da intensidade de sinal em 71,4% em T1-BB e T1-FSBB, 85,7% em T2-BB e 71,4% em T2-FSBB. Nas placas tipo 1 houve aumento da intensidade de sinal em 50,0% em T1 e T2. Em 19 segmentos a US foi considerada normal. Quando estes segmentos foram avaliados pela RM, houve aumento da intensidade de sinal em 47,4% em T1-BB, 57,9% em T1-FSBB e 52,6% em T2-BB e T2-FSBB. CONCLUSÃO: Houve alta incidência de aterosclerose carotídea. Houve reprodutibilidade marginal na associação entre o grau de estenose visualizado pela UDC e ARM. Não houve correlação entre os tipos de ecogenicidade das placas visualizadas pela US com as alterações de intensidade de sinal pela RM. A qualidade de imagens dos exames de RM foi considerada ótima em T1 e T2 e muito boa em 3D TOF (axial). A qualidade de imagem dos exames de ARM foi excelente. Notou-se ótima reprodutibilidade interobservadores, com valores de índice kappa acima de 0,71.

Alterações parenquimatosas na trombose venosa cerebral: aspectos da ressonância magnética e da angiorressonância

OBJETIVO: Determinar a freqüência e localização das alterações parenquimatosas da trombose venosa cerebral nos exames de ressonância magnética e de angiorressonância, bem como a correlação com o território e a drenagem venosa comprometida. MATERIAIS E MÉTODOS: Foram analisados exames de 21 pacientes realizados entre 1996 e 2004, com diagnóstico clínico e radiológico de trombose venosa cerebral em exames de ressonância magnética e de angiorressonância nas seqüências 2D PC, 3D PC e 3D TOF com contraste paramagnético. Análise estatística foi realizada com o teste do qui quadrado. Quatro pacientes tinham exames de controle e três realizaram angiografia por subtração digital. RESULTADOS: Dos 21 pacientes, 18 eram mulheres, todos com idade entre três e 82 anos (média de 40 anos e mediana de 36 anos). Os principais fatores etiológicos foram infecção, uso de contraceptivos orais, reposição hormonal e colagenoses. Predominaram os sintomas de déficit focal, cefaléia, alteração do nível de consciência e convulsões. Por freqüência, as manifestações parenquimatosas foram: edema/infarto de distribuição cortical e/ou subcortical, congestão venosa e circulação colateral, realce meníngeo e infarto ou edema dos tálamos e núcleos da base. Os principais seios comprometidos foram o sagital superior, o transverso esquerdo, o sigmóide esquerdo e o seio reto, sendo incomum o acometimento dos seios cavernosos e de veias corticais. CONCLUSÃO: A trombose venosa cerebral é causa incomum de acidente vascular encefálico, com prognóstico favorável pelo caráter reversível das lesões. Seu diagnóstico depende fundamentalmente da capacidade do radiologista reconhecer suas formas de apresentação, principalmente nos casos em que ele é sugerido pelas alterações parenquimatosas e não necessariamente pela visualização do trombo. A precisão e a rapidez no diagnóstico permitem o pronto tratamento, reduzindo a morbi-mortalidade da doença.

Irradiação de polímeros com feixe de elétrons: caracterização de íons positivos através da técnica de tempo-de-vôo

With the aim of studying the interaction of fast electrons with solid surfaces we have developed an experimental set-up based on electron stimulated desorption (ESD) coupled to time-of-flight (TOF) mass spectrometry. Poly(methyl methacrylate) and poly(vynil chloride) samples have been irradiated by a pulsed electron beam of 1.2 keV and 0.18 µs FWHM. The results show that H+ is the main ionic species to desorb after electron bombardment. In addition, other ionic fragments were also observed and assigned. These results show the potentiality of this technique in the study of ESD of polymers.

Dessorção iônica e degradação de filmes de polipirrol dopado com dodecilsulfato induzidas por elétrons de alta energia

Electron stimulated ion desorption (ESID) and degradation studies of polypyrrole doped with dodecylsulfate (PPy/DS) deposited on FTO were performed using time-of-flight mass spectrometry (TOF-MS) for ion analysis. The results suggest a strong contribution from fragments of the dodecylsulfate hydrocarbon chain to the mass spectra. In the 650-1500 eV energy range the ion yield curves show maxima at about 600, 1200 and 1400 eV, which can be related to carbon, nitrogen and oxygen-containing fragments, respectively, and interpreted in terms of the Auger Stimulated Ion Desorption (ASID) mechanism. Degradation studies indicate rapid loss of heavier hydrocarbons and an increase of bulk and substrate fragments. Some degradation profiles suggest formation of new species.

Sintesis de poliuretanos a partir de polioles obtenidos a partir del aceite de higuerilla modificado por transesterificación con pentaeritritol

Castor oil was reacted by transesterification with various percentages in mass of pentaerythritol to obtain different esters of pentaerythritol. Alternatively, glycerol was also used instead of pentaerythritol for the same reaction in order to establish comparative reference products. The products of the reactions were characterized by matrix-assisted laser desorption/ionization time-of-flight mass spectroscopy in order to detect and quantify (in terms of the molecular mass and structural information) the components of the products obtained. Analysis for hydroxyl value, acid value, viscosity and specific gravity were used to complete the characterization of the polyols obtained and also of the original castor oil. The polymer characterization was accomplished by tensile stress-strain tests, Shore A hardness, thermogravimetric analysis and chemical resistance to solvents.

Caracterização de contaminantes presentes em sistemas de tratamento de esgotos, por cromatografia líquida acoplada à espectrometria de massas tandem em alta resolução

This work shows results on the characterization, by liquid chromatography coupled to high resolution tandem mass spectrometry (LC-IT-TOF-MS) with electrospray ionization, of organic compounds present in raw and treated effluents from a combined sewage treatment systems (upflow anaerobic sludge blanket-trickling filter). The sewage samples were prepared by C18 solid phase extraction and the spectra obtained from the various extracts were submitted to principal component analysis to evaluate their pattern and identify the major deprotonated species. Some target compounds were submitted to semiquantitative analysis, using phenolphtalein as internal standard. The results showed the anaerobic step had little impact on the removal of anionic surfactants (LAS), fatty acids, and some contaminantes such as bisphenol A and bezafibrate, whereas the aerobic post-treatment was very efficient in removing these organics.