Deconjugation Kinetics of Glucuronidated Phase II Flavonoid Metabolites by B-glucuronidase from Neutrophils

Flavonoids are inactivated by phase II metabolism and occur in the body as glucuronides. Mammalian ß-glucuronidase released from neutrophils at inflammatory sites may be able to deconjugate and thus activate flavonoid glucuronides. We have studied deconjugation kinetics and pH optimum for four sources of ß-glucuronidase (human neutrophil, human recombinant, myeloid PLB-985 cells, Helix pomatia) with five flavonoid glucuronides (quercetin-3-glucuronide, quercetin-3'-glucuronide, quercetin-4'-glucuronide, quercetin-7-glucuronide, 3'-methylquercetin-3-glucuronide), 4-methylumbelliferyl-ß-D-glucuronide, and para-nitrophenol-glucuronide. All substrate-enzyme combinations tested exhibited first order kinetics. The optimum pH for hydrolysis was between 3.5-5, with appreciable hydrolysis activities up to pH 5.5. At pH 4, the Km ranged 44-fold from 22 µM for quercetin-4'-glucuronide with Helix pomatia ß-glucuronidase, to 981 µM for para-nitrophenol-glucuronide with recombinant ß-glucuronidase. Vmax (range: 0.735-24.012 µmol·min-1·unit-1 [1 unit is defined as the release of 1 µM 4-methylumbelliferyl-ß-D-glucuronide per min]) and the reaction rate constants at low substrate concentrations (k) (range: 0.002-0.062 min-1·(unit/L)-1 were similar for all substrates-enzyme combinations tested. In conclusion, we show that ß-glucuronidase from four different sources, including human neutrophils, is able to deconjugate flavonoid glucuronides and non-flavonoid substrates at fairly similar kinetic rates. At inflammatory sites in vivo the pH, neutrophil and flavonoid glucuronide concentrations seem favorable for deconjugation. However, it remains to be confirmed whether this is actually the case

Literatuuronderzoek HPLC-methoden voor vitamine E

Doel van dit onderzoek is: het inventariseren van HPLC-methoden voor vitamine E, eventueel in combinatie met vitamine A, in levensmiddelen. Een overzicht van de in de literatuur beschreven HPLC-methoden vanaf ca. 1977 wordt gegeven

Respiratory Depression in Young Prader Willi Syndrome Patients following Clonidine Provocation for Growth Hormone Secretion Testing

Objectives. To determine the sedative and respiratory effects of clonidine when used to evaluate growth hormone (GH) secretion in children with Prader Willi Syndrome (PWS). Methods. The study prospectively evaluated children with PWS who received clonidine (0.15 mg/m2) to assess GH responsiveness. Patients were studied up to four times over three years. Vital signs, oxygen saturation, and sedation level were recorded at baseline and every five minutes following clonidine. Changes between baseline and post-clonidine were evaluated using a repeated measurement analysis. Results. Sixty studies were performed on 17 patients, mean age 30.4 ± 15.0 months. The mean ± SD dose of clonidine was 0.074 ± 0.027 mg (5.3 ± 1.72 mcg/kg). All patients achieved a sedation score of 4 to 5 (drowsy to asleep). Mean declines in respiratory rate (7.5 ± 6.1 breaths/min; P < .001), and oxygen saturation (2.2 ± 2.0%; P < .001) occurred following clonidine. Five patients (29%) experienced oxygen saturations ≤94% on nine occasions. Three oxygen desaturations were accompanied by partial airway obstruction. Conclusions. Clonidine doses to assess GH secretion often exceed doses used for sedation and result in significant respiratory depression in some children with PWS. There was no association between oxygen desaturation and BMI

Diseño de issim y evaluación de algoritmos de Enrutamiento con calidad de servicio

ISSIM es un simulador por eventos discretos diseñado para evaluar algoritmos de enrutamiento con y sin capacidad de calidad de servicio en el contexto de la arquitectura actual de Internet, Mejor Esfuerzo, y la arquitectura de Servicios Integrados. ISSIM es una herramienta que permite construir las topologías de simulación en forma gráfica y los resultados son entregados en un formato compatible con una hoja de cálculo. Este nuevo simulador fue diseñado para poder comparar los tres algoritmos de enrutamiento, SPF (Shortest Path First) y QOSPF (Quality of Service Shortest Path First) precálculo y en demanda, bajo las mismas condiciones. Entre los resultados obtenidos se encuentran la determinación de la complejidad de las variantes con calidad de servicio del algoritmo de Dijkstra (precálculo y en demanda), el impacto en tiempo de procesamiento y en ancho de banda consumido

Controle da ferrugem asiática da soja com diferentes épocas de aplicação de fungicidas.

O objetivo do trabalho foi avaliar a resposta de linhagens da cultura da soja a diferentes épocas de aplicação de fungicidas no controle da ferrugem asiática. O experimento foi conduzido em condições de campo no Instituto Federal do Triângulo Mineiro- campus Uberaba. Foram utilizadas 2 linhagens promissoras (resistentes a ferrugem asiática) do Programa de Melhoramento Genético da Embrapa, EPAMIG/Fundação Triângulo (BRSMG 771F e MGBR08-77511) além de uma cultivar suscetível (BRSMG Vencedora) do mesmo programa e quatro épocas de aplicação de fungicida (Piraclostrobina & Epoxiconazol 0,50+ óleo mineral 0,5% dose L p.c.ha-1): T1- testemunha (sem aplicação de fungicida) T2- aplicação na fase R1+ 20 dias + 20 dias, T3- aplicação primeiras pústulas + retorno das pústulas+ retorno das pústulas, T4- aplicação primeiras pústulas + 20 dias após primeiras pústulas + R5.1, T5- aplicação na fase R5.1. A aplicação dos fungicidas foram efetuadas utilizando um pulverizador costal. O delineamento experimental utilizado foi um fatorial em blocos ao acaso 3x5x4 (3 linhagens x 5 épocas de aplicação de fungicidas x 4 repetições) totalizando 15 tratamentos. As parcelas experimentais constam de quatro linhas com seis metros de comprimento por dois metros de largura e o espaçamento entrelinhas de 0,5 metros. Após duas avaliações, observa-se para os tratamentos com variedades resistentes a ferrugem, que ocorre um atraso no início da doença no campo. Porém, ainda faz-se necessário avaliar o comportamento de tais materiais em condições de alta pressão de inoculo, o que ocorrerá até o fim do ciclo da cultura

Regioselective synthesis of plant (iso)flavone glycosides in Escherichia coli

The flavonoids genistein, biochanin A, luteolin, quercetin, and kaempferol are plant natural products with potentially useful pharmacological and nutraceutical activities. These natural products usually exist in plants as glycosides, and their glycosylation has a remarkable influence on their pharmacokinetic properties. The glycosyltransferases UGT71G1 and UGT73C8 from Medicago truncatula are excellent reagents for the regioselective glycosylation of (iso)flavonoids in Escherichia coli grown in Terrific broth. Ten to 20 mg/L of either genistein or biochanin A 7-O-glucoside was produced after feeding genistein or biochanin A to E. coli expressing UGT71G1, and similar levels of luteolin 4’-O- and 7-O-glucosides were produced after feeding luteolin to cultures expressing UGT73C8. For the production of kaempferol 3-O-glucoside or quercetin 3-O-glucoside, the Phe148Val or Tyr202Ala mutants of UGT71G1 were employed. Ten to 16 mg/L of either kaempferol 3-O- or quercetin 3-O-glucosides were produced on feeding kaempferol or quercetin to E. coli expressing these enzymes. More than 90% of the glucoside products were released to the medium, facilitating their isolation

Hypoxia-inducible factor-1 (HIF-1) pathway activation by quercetin in human lens epithelial cells

Quercetin is a dietary bioflavonoid which has been shown to inhibit lens opacification in a number of models of cataract. The objectives of this study were to determine gene expression changes in human lens epithelial cells in response to quercetin and to investigate in detail the mechanisms underlying the responses. FHL-124 cells were treated with quercetin (10 µM) and changes in gene expression were measured by microarray. It was found that 65% of the genes with increased expression were regulated by the hypoxia-inducible factor-1 (HIF-1) pathway. Quercetin (10 and 30 µM) induced a time-dependent increase in HIF-1a protein levels. Quercetin (30 µM) was also responsible for a rapid and long-lasting translocation of HIF-1a from the cytoplasm to the nucleus. Activation of HIF-1 signaling by quercetin was confirmed by qRT–PCR which showed upregulation of the HIF-1 regulated genes EPO, VEGF, PGK1 and BNIP3. Analysis of medium taken from FHL-124 cells showed a sustained dose-dependent increase in VEGF secretion following quercetin treatment. The quercetin-induced increase and nuclear translocation of HIF-1a was reversed by addition of excess iron (100 µM). These results demonstrate that quercetin activates the HIF-1 signaling pathway in human lens epithelial cells

Capacity development in food composition database management and nutritional research and education in Central and Eastern European, Middle Eastern and North African countries

Background/Objectives: Capacity development (CD) in food and nutrition is much more than formal training and includes human resource development, and organisational, institutional and legal framework development with the aim of enhancing nutrition-relevant knowledge and skills to support infrastructural development. The goal of the European Food Information Resource (EuroFIR) Network of Excellence has been to develop and integrate food composition data throughout Europe. EuroFIR joined forces in CD with the United Nations (UN) University and UN System Standing Committee on Nutrition, the Network for Capacity Development in Nutrition in Central and Eastern Europe, the Central and Eastern European Countries Food Data Systems network and with the Middle East and North African Capacity Building Initiative. The aim of this paper is to discuss an inventory of the status of food composition databases (FCDBs) and the training needs of compilers in non-EuroFIR countries in Central and Eastern Europe (CEE) and in the Middle East and North Africa (MENA), and to present the CD achieved through EuroFIR and other network collaborations. Subjects/Methods: Two online questionnaires were created addressing the FCDB status and specific training needs in countries of the targeted regions. Data were collected during 2006-2008 and then analysed. Subsequently, CD activities were organised. Results: Contacts were established in 19 CEE and 7 MENA countries, of which several had national food composition tables, but no electronic versions. Education, training, workshops, networking and the sharing of experiences were uniformly requested. Subsequently, CD activities in EuroFIR were organised focussing on food composition courses, exchange visits, workshops and individual training for PhD students, junior scientists and other staff categories, as well as conferences linked to food composition research and food information. To facilitate CD activities, EuroFIR has signed a Memorandum of Understanding with the Czech Republic, Hungary, Slovenia, Croatia and Estonia. Conclusions: EuroFIR has created training activities that complement national activities. Collaboration with other networks has provided an overview of FCDB status and training needs, providing directions for CD activities in those countries. This provides a platform for new funding and further development and networking for CD, which would be conducive to European Commission objectives and public health strategies for CD. European Journal of Clinical Nutrition (2010) 64, S134-S138; doi:10.1038/ejcn.2010.22