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Biomedical subjects

I C Oliveira

Publications and source records attributed to I C Oliveira.

12 recordsLinked to original sources
PubMed2005

Grid requirements for the integration of biomedical information resources for health applications.

OBJECTIVES: The goal of this paper is to identify how Grid technology can be applied for the development and deployment of integration systems, bringing together distributed and heterogeneous biomedical information sources for medical applications. METHODS: The integration of new genetic and medical knowledge in clinical workflows requires the development of new paradigms for information management in which the ability to access and relate disparate data sources is essential. We adopt a requirements perspective based on the user needs we have identified in the development of the INFOGENMED system to assess current Grid technology against those requirements. RESULTS: The gap between Grid features and distributed biomedical information integration needs is characterized. Results from prospective studies are also reported. CONCLUSIONS: Grid infrastructures offer advanced features for the deployment of collaborative computational environments across virtual organizations. New Grid developments are in line with the problem of multiple site information integration. From the INFOGENMED point of view, Grid infrastructures need to evolve to implement structured data access services and semantic content description and discovery.

Computational Biology↗
PubMed2001

Genomic characterization of wild-type measles viruses that circulated in different states in Brazil during the 1997 measles epidemic.

Despite the marked reduction in the incidence of measles in Brazil, a measles epidemic occurred in this country in 1997. The measles cases observed during this epidemic began to reappear in large numbers in São Paulo, and spread to Rio de Janeiro and other Brazilian states. In the present study molecular biology techniques were used for the detection and genomic characterization of measles viruses from clinical samples such as urine and nasopharyngeal secretions collected in the states of Rio de Janeiro, Minas Gerais and Paraná, during the 1997 epidemic. RT-PCR and nucleotide sequence analysis of part of the carboxyl-terminal region of the nucleoprotein gene of measles viruses obtained directly from clinical samples or from infected cell cultures during this epidemic classified all as wild-type of genotype D6. As the genotype D6 was identified in different Brazilian states, this study demonstrated that this genotype was circulating in Brazil during the 1997 epidemic.

Adult↗
PubMed2001

Metabolite and light regulation of metabolism in plants: lessons from the study of a single biochemical pathway.

We are using molecular, biochemical, and genetic approaches to study the structural and regulatory genes controlling the assimilation of inorganic nitrogen into the amino acids glutamine, glutamate, aspartate and asparagine. These amino acids serve as the principal nitrogen-transport amino acids in most crop and higher plants including Arabidopsis thaliana. We have begun to investigate the regulatory mechanisms controlling nitrogen assimilation into these amino acids in plants using molecular and genetic approaches in Arabidopsis. The synthesis of the amide amino acids glutamine and asparagine is subject to tight regulation in response to environmental factors such as light and to metabolic factors such as sucrose and amino acids. For instance, light induces the expression of glutamine synthetase (GLN2) and represses expression of asparagine synthetase (ASN1) genes. This reciprocal regulation of GLN2 and ASN1 genes by light is reflected at the level of transcription and at the level of glutamine and asparagine biosynthesis. Moreover, we have shown that the regulation of these genes is also reciprocally controlled by both organic nitrogen and carbon metabolites. We have recently used a reverse genetic approach to study putative components of such metabolic sensing mechanisms in plants that may be conserved in evolution. These components include an Arabidopsis homolog for a glutamate receptor gene originally found in animal systems and a plant PII gene, which is a homolog of a component of the bacterial Ntr system. Based on our observations on the biology of both structural and regulatory genes of the nitrogen assimilatory pathway, we have developed a model for metabolic control of the genes involved in the nitrogen assimilatory pathway in plants.

Amino Acids, Dicarboxylic↗
PubMed1999

Carbon and amino acids reciprocally modulate the expression of glutamine synthetase in Arabidopsis.

In bacteria and yeast, glutamine synthetase (GS) expression is tightly regulated by the metabolic status of the cell, both at the transcriptional and posttranscriptional levels. We discuss the relative contributions of light and metabolic cues on the regulation of members of the GS gene family (chloroplastic GS2 and cytosolic GS1) in Arabidopsis. These studies reveal that the dramatic induction of mRNA for chloroplastic GS2 by light is mediated in part by phytochrome and in part by light-induced changes in sucrose (Suc) levels. In contrast, the modest induction of mRNA for cytosolic GS1 by light is primarily mediated by changes in the levels of carbon metabolites. Suc induction of mRNA for GS2 and GS1 occurs in a time- and dose-dependent manner. Suc-induced changes in GS mRNA levels were also observed at the level of GS enzyme activity. In contrast, amino acids were shown to antagonize the Suc induction of GS, both at the level of mRNA accumulation and that of enzyme activity. For GS2, the gene whose expression was the most dramatically regulated by metabolites, we used a GS2 promoter-beta-glucuronidase fusion to demonstrate that transcriptional control is involved in this metabolic regulation. Our results suggest that the metabolic regulation of GS expression in plants is controlled by the relative abundance of carbon skeletons versus amino acids. This would allow nitrogen assimilation into glutamine to proceed (or not) according to the metabolic status and biosynthetic needs of the plant. This type of GS gene regulation is reminiscent of the nitrogen regulatory system in bacteria, and suggests an evolutionary link between metabolic sensing and signaling in bacteria and plants.

Amino Acids↗
PubMed1996

Arabidopsis mutant analysis and gene regulation define a nonredundant role for glutamate dehydrogenase in nitrogen assimilation.

Glutamate dehydrogenase (GDH) is ubiquitous to all organisms, yet its role in higher plants remains enigmatic. To better understand the role of GDH in plant nitrogen metabolism, we have characterized an Arabidopsis mutant (gdh1-1) defective in one of two GDH gene products and have studied GDH1 gene expression. GDH1 mRNA accumulates to highest levels in dark-adapted or sucrose-starved plants, and light or sucrose treatment each repress GDH1 mRNA accumulation. These results suggest that the GDH1 gene product functions in the direction of glutamate catabolism under carbon-limiting conditions. Low levels of GDH1 mRNA present in leaves of light-grown plants can be induced by exogenously supplied ammonia. Under such conditions of carbon and ammonia excess, GDH1 may function in the direction of glutamate biosynthesis. The Arabidopsis gdh-deficient mutant allele gdh1-1 cosegregates with the GDH1 gene and behaves as a recessive mutation. The gdh1-1 mutant displays a conditional phenotype in that seedling growth is specifically retarded on media containing exogenously supplied inorganic nitrogen. These results suggest that GDH1 plays a nonredundant role in ammonia assimilation under conditions of inorganic nitrogen excess. This notion is further supported by the fact that the levels of mRNA for GDH1 and chloroplastic glutamine synthetase (GS2) are reciprocally regulated by light.

Amino Acid Sequence↗
PubMed1996

CCAAT box enhancer binding protein alpha (C/EBP-alpha) stimulates kappaB element-mediated transcription in transfected cells.

A construct comprising three tandemly repeated copies of the kappaB element from the interleukin-8 gene linked to chloramphenicol acetyltransferase (CAT) (3xNF-kappaBCAT) was transcriptionally activated in normal human FS-4 fibroblasts by co-transfection with expression vectors for NF-kappaB p50, p65, or p52. Unexpectedly, a significant activation of 3xNF-kappaBCAT was also seen upon its co-transfection with the expression vector for CCAAT box enhancer binding protein alpha (C/EBP-alpha) (but not C/EBP-beta or C/EBP-delta). Stimulation by C/EBP-alpha required some other factor(s) present in FS-4 cells because no transcriptional activation of 3xNF-kappaBCAT was seen after co-transfection with C/EBP-alpha in F9 mouse embryonic carcinoma cells, known to be deficient in several transcription factors. To determine whether transcriptional activation was the result of interaction with one of the major NF-kappaB proteins, we co-transfected C/EBP-alpha with NF-kappaB p50, p65, p50 + p65, or p52 into F9 or FS-4 cells. No cooperative interaction was seen; in fact, C/EBP- alpha reduced p65-stimulated transcription, especially in F9 cells. Electrophoretic mobility shift assay with a kappaB probe revealed that the addition of recombinant C/EBP-alpha protein to nuclear extracts from untreated FS-4 cells resulted in the appearance of four bands. Only one of these bands was supershifted by antibody to p50, whereas antibodies to p65 or other NF-kappaB proteins had no effect. Our findings show that C/EBP-alpha may cause activation of some kappaB element-containing genes lacking C/EBP binding sites.

Animals↗
PubMed1996

[Views of nursing students on the curriculum development in night service].

This preliminary work was based in the qualitative method, about the opinion of the College students nursing in the seventh (7th) stage of the course about the development of the curricular experience on the night shift. Thirty (30) relates were identified in the respective aspects: importance of the experiences, relationship between overseer nurse and multidisciplinary health care team; difference between day shift and night shift. The most part of the related demonstrates that it's been valid and they've given emphasis, only, in relationship between overseer nurse and multidisciplinary health care team, without emphasizing the effective contribution on the practice knowledge. The relating emphasized the difference among the shifts. It follows that is necessary an extense discussion of the teachers, nursing body and college students nursing body, under the effective objectives of the practice curricular experience for professional qualification.

Attitude of Health Personnel↗
PubMed1994

Transcriptional inhibition of the interleukin-8 gene by interferon is mediated by the NF-kappa B site.

The cytokine interleukin-8 (IL-8) is an important mediator of neutrophil, lymphocyte, and basophil chemotaxis and activation. Earlier we demonstrated that beta interferon (IFN-beta) can inhibit tumor necrosis factor (TNF)-induced IL-8 gene expression at the transcriptional level, apparently by a novel mechanism. To define the cis-acting elements and trans-acting factors involved in this inhibition, DNA constructs containing portions of the 5'-flanking region of the IL-8 gene were linked to the chloramphenicol acetyltransferase (CAT) reporter gene and transfected into human diploid FS-4 fibroblasts. The region spanning positions -98 to +44 was sufficient to confer both inducibility by TNF and inhibition by simultaneous treatment with IFN-beta. Inhibition of TNF- or IL-1-induced CAT activity by IFN-beta or IFN-alpha was also observed when a DNA fragment containing only the NF-IL-6 and NF-kappa B sites (positions -94 to -70) was placed upstream of the homologous or a heterologous minimal promoter. A construct containing three copies of the NF-kappa B element in front of the CAT gene also was inducible by TNF, and this stimulatory effect too was inhibited by IFN-beta, indicating that the NF-kappa B element is sufficient to confer inhibition by IFN-beta. This inhibitory effect was specific for the NF-kappa B site of the IL-8 gene since it was less marked with constructs containing three copies of the NF-kappa B site from the HLA-B7 gene. Gel shift assays with a probe containing the NF-kappa B and NF-IL-6 binding sites of the IL-8 gene (positions -101 to -63) showed that IFN-beta treatment did not block the activation of NF-kappa B proteins or their ability to bind to the NF-kappa B site. However, nuclear extracts from cells treated with TNF in the presence of IFN-beta gave rise to an additional band that appears to contain protein components from the NF-kappa B and NF-IL-6 families. NF-kappa B site-mediated suppression of IL-8 gene expression by IFN-beta represents a hitherto unknown mechanism and target of IFN action.

Base Sequence↗
PubMed1994

Recent progress in the elucidation of interferon-gamma actions: molecular biology and biological functions.

It has been known for a long time that the two major classes of interferons, IFN-alpha/beta and IFN-gamma, are similar in many of their actions despite the fact that they are structurally unrelated and bind to separate receptors. Recent studies revealed overlapping, common components in IFN-alpha/beta and IFN-gamma signaling. The second chain of the IFN-gamma receptor was recently identified. The generation of mice with targeted disruptions of the genes for IFN-gamma or the IFN-gamma receptor is helping to understand the essential functions of IFN-gamma in host defenses. Other studies have shown that the transcription factor IRF-1 is essential for the IFN-gamma-mediated activation of the gene for the inducible nitric oxide synthase.

Animals↗
PubMed1992

Downregulation of interleukin 8 gene expression in human fibroblasts: unique mechanism of transcriptional inhibition by interferon.

The chemotactic cytokine interleukin 8 (IL-8) is produced upon stimulation by various agents in many cell types, including connective-tissue fibroblasts. Tumor necrosis factor (TNF) and IL-1 are potent inducers of IL-8 expression. Earlier we showed that TNF-induced stimulation of IL-8 mRNA accumulation in human FS-4 fibroblasts was inhibited by interferon beta (IFN-beta) or IFN-gamma. Here we show that this inhibition is not specific for TNF, since IFN-beta also reduced IL-8 mRNA accumulation induced by IL-1 or the double-stranded RNA poly (I-C). Treatment with IFN-beta also decreased TNF-induced IL-8 protein accumulation. Interestingly, the inhibitory effect was much less pronounced when IFN-beta was added greater than or equal to 1 hr before TNF. The inhibitory action of IFN-beta on IL-8 mRNA accumulation was undiminished in the presence of inhibitors of protein synthesis. Nuclear run-on assays demonstrated that IFN-beta caused a marked inhibition of TNF-induced IL-8 gene transcription; the transcriptional activation of several other TNF-induced genes was not inhibited by IFN-beta. The results suggest that the specific inhibition of the transcriptional activation of IL-8 by IFN is due either to a transient inactivation of a factor required for IL-8 transcription or to the activation of a selective inhibitory factor.

Cell Line↗
PubMed1989

[The biopsychosocial characteristics and forms of caring for 0- to 12-month-old infants perceived by the mothers attending a mother-child service in the city of Rio de Janeiro].

The paper studied the perception of mothers related to biopsychosocial characteristics during first year of life. The results suggested that the mothers are not informed on the characteristics. The variables studied influenced the perception of the biological characteristics and forms of attending children in opposition to the motor and psychosocial characteristics.

Adult↗