Drosha, DGCR8, and Dicer mRNAs are down-regulated in human cells infected with dengue virus 4, and play a role in viral pathogenesis.

Dengue virus (DENV) and its four serotypes (DENV1-4) belong to the Flavivirus genus of the Flaviviridae family. DENV infection is a life-threatening disease, which results in up to 20,000 deaths each year. Viruses have been shown to encode trans-regulatory small RNAs, or microRNAs (miRNAs), which bind to messenger RNA and negatively regulate host or viral gene expression. During DENV infections, miRNAs interact with proteins in the RNAi pathway, and are processed by ribonucleases such as Dicer and Drosha. This study aims to investigate Drosha, DGCR8, and Dicer expression levels in human A-549 cells following DENV4 infection. DENV4 infected A-549 cells were collected daily for 5 days, and RNA was extracted to quantify viral load. Gene expression of Drosha, Dicer, and DGCR8 was determined using quantitative PCR (RT-qPCR). We found that DENV4 infection exhibited the highest viral load 3 days post-infection. Dicer, Drosha, and DGCR8 showed reduced expression following DENV4 infection as compared with negative controls. In addition, we hypothesize that reduced expression of DGCR8 may not only be related to miRNA biogenesis, but also other small RNAs. This study may change our understanding regarding the relationship between host cells and the dengue virus.

Phenol electrooxidation on Fe-Co3O4 thin film electrodes in alkaline medium.

Fe-Co(3)O(4) thin film with different amounts of Fe have been used for the electro-oxidation of phenol in alkaline medium at room temperature. The electrodes were prepared by coating stainless steel supports with successive layers of the oxides, obtained by thermal decomposition at 673 K. The electrolysis was carried out at constant potential and the phenol disappearance, during the electrolysis, was monitored by UV-Vis absorbance measurements between 250 and 500 nm. After 3 h of electrolysis, the intermediates were identified by comparing the HPLC data and UV-Vis spectra to those from pure standards. The results indicate that the same oxidation products are formed on the different prepared electrodes, namely the decomposition products of phenol such as benzoquinone, hydroquinone and cathecol in basic medium. Simulated results show clearly the decrease of the amount of phenolic species with the electrolysis time. An enhancement of the phenol removal is observed with the presence of iron in the oxide. Under the operating conditions, around 30% of the initial phenol has been removed at ca. 3 h and the complete degradation is obtained after 54 h of electrolysis, when Fe-Co(3)O(4) thin film with 10% of Fe is used as anode.

Photocatalytic decolorization of methylene blue in the presence of TiO2/ZnS nanocomposites.

The synthesis of distinct nanocrystalline TiO2 capped ZnS samples was carried out using a chemical deposition method. The materials characterization showed that the presence of ZnS onto TiO2 surface results in a red shift of the material band edge when compared with the initial semiconductor. The photocatalytic activity of the prepared nanocomposites was tested on the decolorization of methylene blue (MB) aqueous solutions. The dye photodecolorization process was studied considering the influence of experimental parameters such as catalyst concentration, TiO2/ZnS ratio, pH and methylene blue adsorption rate. The material with the best catalytic activity towards the methylene blue photodecolorization was the TiO2 doped with 0.2% of ZnS. The complete photodecolorization of a 20ppm methylene blue solution, at natural pH was achieved in less than 20min, nearly 70min faster than the TiO2 photoassisted process.

MR imaging of ductal carcinoma in situ.

PURPOSE: To investigate the ability of magnetic resonance (MR) imaging to depict ductal carcinoma in situ (DCIS). MATERIALS AND METHODS: Between January 1992 and April 1996, 330 women underwent MR imaging before excisional biopsy. Of these, 101 women had carcinoma, 19 of whom had DCIS. The MR imaging findings in the 19 women were reviewed. RESULTS: Thirteen of 19 patients had pure DCIS. The mean lesion diameter was 10 mm (range, 2-22 mm). MR imaging enabled identification of DCIS in 10 (77%) of the 13 cases as ductal enhancement (n = 6), regional enhancement (n = 3), or a peripherally enhancing mass (n = 1). The three lesions not identified had a mean diameter of 3.7 mm. Six of 19 patients had both DCIS and an invasive cancer. In four of these patients, DCIS was identified only at MR imaging (mean diameter, 3 mm). In two of six patients, DCIS was not identified at MR imaging. CONCLUSION: MR imaging can depict mammographically visible and occult foci of DCIS. Some small foci of DCIS detected at mammography and histologic examination, however, may be occult at MR imaging.

Os caminhos da descentralizaçäo no setor saúde brasileiro / Descentralization ways in the Brazilian health sector

Aborda à luz do debate atual sobre o poder local, o processo de descentralizaçäo dos serviços de saúde no Brasil. Trata essa questäo central tendo por eixo a implementaçäo da Lei do SUS em geral, e no particular as questöes de financiamento e de desenvolvimento de recursos humanos. Conclui, apresentando alternativas no sentido de levar a uma maior autonomia local

[The organization of health services: the comparison as contribution]. / Organização dos serviços de saúde: a comparação como contribuição.

This article discusses about a recent procedure in health care studies, the comparison as a methodology of analysis. The different analytical currents refer to a particular method of understanding health-disease process. They are: functionalism, the historical-materialism and the new currents. Their phylosophical and sociological basis, concepts, analysis instruments and purposes are showed here by a review of the principal works from representative authors as Navarro, Terris, Roemer, Fry, Illich, Capra and others. The paper suggests that comparative analysis can take two directions: the first is a operational approach for analysing the concrete situations of health's service organization, the second, a more conceptual one, aimed at identifying critical questions and international tendencies in health's systems. The recent discussion search for the overcoming of these dichotomies toward the progress of the production of knowledge and its effects in health's services organization.

A new enzymatic activity participating in the initiation of glycogen biosynthesis in rat brain.

A rat brain extract, able to synthesize from UDP-Glc an alpha-1,4-glucan covalently bound to a protein in the absence of added primer is described. The compound formed is precipitable by dilute trichloroacetic acid (TCA). In the presence of glycogen, added as primer, this molecule is enlarged and is not precipitable by TCA. Unprimed and primed activities differ in several aspects, such as the behavior in the presence of some effectors, and the optimum pH. Umprimed and primed activities presented two pHs optima, both sharing only one. The proteoglucans synthesized under the different pHs gave different patterns after analysis under denaturing PAGE and the oligosaccharides synthesized on the protein backbone differ in the glucosyl length. It is concluded that also in rat brain, the initiation process of glycogen biosynthesis is mediated through the formation of a glycoprotein. Our present results showed that the step of the putative "Glycogen Initiator" proposed by use before, requires two enzymes UDPGlc-transglucosylating activities, Glycogen Initiator 1 and Glycogen Initiator 2, before Glycogen Synthase in the alpha-1,4-glucosidic linkages formation.

Intra- and extracellular forms of ethanol-modified O-underglycosylated galactose oxidase.

The effect of ethanol and tunicamycin on synthesis and secretion of galactose oxidase was studied in resting cells of Dactylium dendroides. Ethanol promoted an overall decrease in both intra- and extracellular enzyme levels to the same extent that it inhibited [14C]glucosamine incorporation into total protein. The carbohydrate content of the intracellular enzyme was also depressed (44%) with a simultaneous decrease in O-Ser linked oligosaccharides. The intracellular galactose oxidase obtained after exposure of mycelia to ethanol plus tunicamycin lost 86% of its carbohydrate moieties, whereas the extracellular form lost only 35%. In both cases, residual sugar moieties were not eliminated by mild alkaline treatment. These data suggest that ethanol affects O-glycosylation of galactose oxidase. O-Underglycosylation did not affect the S0.5 values for galactose but diminished the molar catalytic activity. The absence of O-Ser/Thr-linked saccharides turned the intracellular enzyme into a form more susceptible to proteolysis than that devoid of N-linked sugars (tunicamycin-treated). O-Underglycosylation had a significant effect on the renaturation-reactivation of the enzyme after denaturation with 2.4 M Gdn-HCl.

Role of carbohydrate content on the properties of galactose oxidase from Dactylium dendroides.

The stability of intracellular, extracellular, and deglycosylated forms of galactose oxidase was compared with respect to the denaturing effects of heat, pH, and guanidine hydrochloride. The highly glycosylated forms were found to be more stable to pH and thermal inactivation. All forms were reversibly denaturated by guanidine hydrochoride, but the extent was dependent on the carbohydrate content. Deglycosylation did not affect the affinity of the enzyme for dihydroxyacetone and galactose. Exposure of different forms of galactose oxidase to proteases like pronase and trypsin resulted in a rapid degradation of the glycoenzymes with the formation of stable products. After pronase digestion of intra- and extracellular forms of galactose oxidase catalytic species were isolated by gel filtration. The species (61 and 42 kDa) isolated from pronase-digested extracellular enzyme lost their ability to oxidize primary alcohols. Species (67 and 46 kDa) obtained from the intracellular enzyme kept the specificity of the original enzyme. Active pronase-derived peptides (42 and 46 kDa, respectively) had a higher carbohydrate content than the inactive ones.

Purification and characterization of intracellular galactose oxidase from Dactylium dendroides.

The intracellular galactose oxidase from Dactylium dendroides was purified to homogeneity with a 64% yield. The enzyme is a glycoprotein (7.7% neutral sugars, 1.7% aminosugars) with 72,000 Da of molecular mass. The enzyme showed nonlinear double reciprocal plots with O2 and D-galactose, suggesting cooperative binding for both substrates. The intracellular galactose oxidase catalyzes the oxidation of galactose derivatives and dihydroxyacetone but not of glycerol, glycolaldehyde, beta-hydroxipyruvate, and allyl alcohol which are substrates for the extracellular enzyme. Compared with the extracellular galactose oxidase, the intracellular enzyme showed higher carbohydrate content and sensitivity to diethyldithiocarbamate.