RESUMO
The last two decades have seen substantially increased potential for quantitative social science research. This has been made possible by the significant expansion of publicly available social science datasets, the development of new analytical methodologies, such as microsimulation, and increases in computing power. These rich resources do, however, bring with them substantial challenges associated with organizing and using data. These processes are often referred to as 'data management'. The Data Management through e-Social Science (DAMES) project is working to support activities of data management for social science research. This paper describes the DAMES infrastructure, focusing on the data-fusion process that is central to the project approach. It covers: the background and requirements for provision of resources by DAMES; the use of grid technologies to provide easy-to-use tools and user front-ends for several common social science data-management tasks such as data fusion; the approach taken to solve problems related to data resources and metadata relevant to social science applications; and the implementation of the architecture that has been designed to achieve this infrastructure.
RESUMO
A novel conjugate of human hemoglobin (Hb) and the nucleoside analogue ribavirin (RBV) was synthesized to demonstrate the utility of Hb as a biocompatible drug carrier for improved drug delivery in the treatment of liver disease. RBV is used in combination with interferon for the treatment of hepatitis C, but its side effects can result in dose limitation or discontinuation of treatment. Targeted delivery of RBV may help to prevent or minimize its toxicity. The hemoglobin-ribavirin conjugate (Hb-RBV) was designed to release bioactive drug upon endocytosis by cells and tissues involved in extracellular Hb catabolism and clearance. Ribavirin-5'-monophosphate (RBV-P) was prepared from RBV and activated as the 5'-monophosphorimidazolide (RBV-P-Im) for reaction with carbonmonoxyhemoglobin to yield Hb-RBV consisting of multiple RBV drugs covalently attached as physiologically labile phosphoramidates via their 5'-hydroxyl groups. A molar drug ratio of six to eight RBV molecules per Hb tetramer was obtained with near complete haptoglobin (Hp) binding of the drug modified Hb maintained. The conjugate complex (Hp-Hb-RBV) was selectively taken up in vitro by cells that express the hemoglobin-haptoglobin receptor, CD163. Recovered ribavirin enzymatically cleaved from Hb-RBV showed equipotent antiproliferative activity compared to control unconjugated RBV against human HepG2 and mouse AML12 liver cell lines. Based upon the reported high level of Hb uptake in the liver, Hb-RBV may be useful in the treatment of certain liver diseases, as well as inflammatory disorders associated with CD163-positive macrophages.
Assuntos
Antivirais/metabolismo , Portadores de Fármacos/metabolismo , Sistemas de Liberação de Medicamentos , Hemoglobinas/metabolismo , Proteínas Recombinantes de Fusão/metabolismo , Ribavirina/metabolismo , Animais , Antígenos CD/metabolismo , Antígenos de Diferenciação Mielomonocítica/metabolismo , Antivirais/química , Linhagem Celular , Portadores de Fármacos/química , Hemoglobinas/química , Hemoglobinas/genética , Humanos , Camundongos , Camundongos Endogâmicos BALB C , Estrutura Molecular , Receptores de Superfície Celular/metabolismo , Proteínas Recombinantes de Fusão/química , Proteínas Recombinantes de Fusão/genética , Ribavirina/químicaRESUMO
CD163, the hemoglobin-haptoglobin receptor, has been reported to be expressed exclusively on monocyte/ macrophages. Here we demonstrate that CD163 is also expressed by a subpopulation of hematopoietic stem/progenitor cells. Flow cytometric analysis shows that 1.9 +/- 1.3% (+/-SD, n = 16) of adult bone marrow and 2.0 +/- 1.8% (n = 8) of umbilical cord blood CD34(+) cells express cell-surface CD163, and 69.1 +/- 16.9% (n = 9) and 79.7 +/- 22.4% (n = 8) of the respective cells contain the CD163 protein intracellularly. The expression of CD163 by CD34(+) cells was confirmed by western blot analysis of cell lysates. Transcripts corresponding to the known predominant and variant 1 forms of CD163 were amplified via RT-PCR from CD34(+) cell-derived mRNA. A new variant (K11) with a deletion at the start of exon 15 was also detected. The deleted region contains a PKCalpha phosphorylation site and an amino acid sequence (YREM) that may support efficient receptor endocytosis. The addition of activating anti-CD163 antibodies increased the growth and differentiation of erythroid progenitors in colony-forming assays. These data suggest that hemoglobin may mediate a stimulatory effect on erythropoiesis through the activation of CD163 on hematopoietic progenitor cells.
