Architecture of high-affinity unnatural-base DNA aptamers toward pharmaceutical applications.

We present a remodeling method for high-affinity unnatural-base DNA aptamers to augment their thermal stability and nuclease resistance, for use as drug candidates targeting specific proteins. Introducing a unique mini-hairpin DNA provides robust stability to unnatural-base DNA aptamers generated by SELEX using genetic alphabet expansion, without reducing their high affinity. By this method, >80% of the remodeled DNA aptamer targeting interferon-γ (KD of 33 pM) survived in human serum at 37 °C after 3 days under our experimental conditions, and sustainably inhibited the biological activity of interferon-γ.

Pattern and predictors of immunologic recovery in HIV infected patients.

Background: Although anti-retroviral therapy has generally improved the survival of HIV infected patients in many developing countries including Ghana, specific socio-demographic factors could still influence outcome of treatment. This study was designed to identify patient-specific factors that could influence the immune recovery of absolute CD4 count in HIV infected patients.

Findings: Hospital records were extracted from two health facilities in Ghana.

LTβR signalling preferentially accelerates oncogenic AKT-initiated liver tumours.

Objectives: The relative contributions of inflammatory signalling and sequential oncogenic dysregulation driving liver cancer pathogenesis remain incompletely understood. Lymphotoxin-β receptor (LTβR) signalling is critically involved in hepatitis and liver tumorigenesis. Therefore, we explored the interdependence of inflammatory lymphotoxin signalling and specific oncogenic pathways in the progression of hepatic cancer.

Mechanism of action for the cytotoxic effects of the nitric oxide prodrug JS-K in murine erythroleukemia cells.

The nitric oxide (NO) prodrug JS-K, a promising anti-cancer agent, consists of a diazeniumdiolate group necessary for the release of NO as well as an arylating ring. In this study, we research the mechanism by which JS-K kills a murine erythroleukemia cell line and determine the roles of NO and arylation in the process. Our studies indicate that JS-K inhibits the PI 3-kinase/Akt and MAP kinase pathways.

The human lung adenocarcinoma cell line EKVX produces an infectious xenotropic murine leukemia virus.

The cell lines of the NCI-60 panel represent different cancer types and have been widely utilized for drug screening and molecular target identification. Screening these cell lines for envelope proteins or gene sequences related to xenotropic murine leukemia viruses (X-MLVs) revealed that one cell line, EKVX, was a candidate for production of an infectious gammaretrovirus. The presence of a retrovirus infectious to human cells was confirmed by the cell-free transmission of infection to the human prostate cancer cell line LNCaP.

Role of N-terminal sequences of the tyrosine kinase sf-Stk in transformation of rodent fibroblasts by variants of Friend spleen focus-forming virus.

Infection of erythroid cells by Friend spleen focus-forming virus (SFFV) leads to acute erythroid hyperplasia in mice, due to expression of its unique envelope glycoprotein, gp55. Erythroid cells expressing SFFV gp55 proliferate in the absence of their normal regulator, erythropoietin, because of the interaction among the viral envelope protein, the erythropoietin receptor, and a short form of the receptor tyrosine kinase Stk (sf-Stk). This leads to constitutive activation of several signal transduction pathways.

Retrovirus-transformed erythroleukemia cells induce central nervous system failure in a new syngeneic mouse model of meningeal leukemia.

Lack of suitable mouse models for central nervous system (CNS)-associated leukemias has hindered mechanism-guided development of therapeutics. By transplanting retrovirus-transformed mouse erythroleukemia cells into syngeneic mice, we developed a new animal model of meningeal leukemia associated with rapid paralysis. Necropsy revealed massive proliferation of the leukemic cells in the bone marrow (BM) followed by pathological angiogenesis and invasion of the leukemic cells into the meninges of the CNS.

Role of phosphatidylinositol 3-kinase in friend spleen focus-forming virus-induced erythroid disease.

Infection of erythroid cells by Friend spleen focus-forming virus (SFFV) leads to acute erythroid hyperplasia in mice due to expression of its unique envelope glycoprotein, gp55. Erythroid cells expressing SFFV gp55 proliferate in the absence of their normal regulator, erythropoietin (Epo), because of interaction of the viral envelope protein with the erythropoietin receptor and a short form of the receptor tyrosine kinase Stk (sf-Stk), leading to constitutive activation of several signal transduction pathways. Our previous in vitro studies showed that phosphatidylinositol 3-kinase (PI3-kinase) is activated in SFFV-infected cells and is important in mediating the biological effects of the virus.

Neurodegeneration induced by PVC-211 murine leukemia virus is associated with increased levels of vascular endothelial growth factor and macrophage inflammatory protein 1 alpha and is inhibited by blocking activation of microglia.

PVC-211 murine leukemia virus (MuLV) is a neuropathogenic retrovirus that has undergone genetic changes from its nonneuropathogenic parent, Friend MuLV, that allow it to efficiently infect rat brain capillary endothelial cells (BCEC). To clarify the mechanism by which PVC-211 MuLV expression in BCEC induces neurological disease, we examined virus-infected rats at various times during neurological disease progression for vascular and inflammatory changes. As early as 2 weeks after virus infection and before any marked appearance of spongiform neurodegeneration, we detected vessel leakage and an increase in size and number of vessels in the areas of the brain that eventually become diseased.

Best practices in implementing lifestyle interventions in the WISEWOMAN program: adaptable strategies for public health programs.

Purpose: Describe best practices for implementing a variety of lifestyle interventions targeting cardiovascular disease risk factors.

Approach: A mixed-methods approach was used to collect and analyze data. The study was guided by the RE-AIM framework.

The tyrosine kinase sf-Stk and its downstream signals are required for maintenance of friend spleen focus-forming virus-induced fibroblast transformation.

Infection of erythroid progenitor cells by Friend spleen focus-forming virus (SFFV) leads to acute erythroid hyperplasia and eventually to erythroleukemia in susceptible strains of mice. The viral envelope protein, SFFV gp55, forms a complex with the erythropoietin receptor (EpoR) and a short form of the receptor tyrosine kinase Stk (sf-Stk), activating both and inducing Epo-independent proliferation. Recently, we discovered that coexpression of SFFV gp55 and sf-Stk is sufficient to transform NIH 3T3 and primary fibroblasts.

Erythroblast transformation by the friend spleen focus-forming virus is associated with a block in erythropoietin-induced STAT1 phosphorylation and DNA binding and correlates with high expression of the hematopoietic phosphatase SHP-1.

Infection of mice with Friend spleen focus-forming virus (SFFV) results in a multistage erythroleukemia. In the first stage, the SFFV envelope glycoprotein interacts with the erythropoietin receptor and a short form of the receptor tyrosine kinase sf-Stk, resulting in constitutive activation of signal transducing molecules and the development of erythropoietin (Epo)-independent erythroid hyperplasia and polycythemia. The second stage results from the outgrowth of a rare virus-infected erythroid cell that expresses nonphysiological levels of the myeloid transcription factor PU.

Feeding Infants and Toddlers Study: meal and snack intakes of Hispanic and non-Hispanic infants and toddlers.

Objective: To describe meal and snack patterns of Hispanic and non-Hispanic infants and toddlers.

Design: A cross-sectional telephone survey in which mothers or other primary caregivers reported their infants' and toddlers' food and beverage intake for a 24-hour period.

Subjects/setting: Subjects were a subset of the national random sample of children aged 4-24 months who participated in the 2002 Feeding Infants and Toddlers Study.

Feeding Infants and Toddlers Study: do vitamin and mineral supplements contribute to nutrient adequacy or excess among US infants and toddlers?

Objective: To report the prevalence of dietary supplement use in a random sample of US infants 4 to 24 months of age, and to compare demographic characteristics, usual nutrient intakes, and food patterns of supplement users and nonusers.

Design: Data from 24-hour recalls collected for the 2002 Feeding Infants and Toddlers Study were analyzed. Recalls included nutrient contributions from dietary supplements as well as all foods and beverages.

The phenomenology of empowerment in collective action.

Recent research has hypothesized that empowerment can arise from collective action through collective self-objectification (CSO), defined as action that actualizes participants' social identity against the power of dominant groups. Activists (N = 37) described several experiences that made them feel empowered (and disempowered). Among the various explanations they offered for these feelings, the most prominent were CSO, unity, and support (or their absence).

Friend spleen focus-forming virus transforms rodent fibroblasts in cooperation with a short form of the receptor tyrosine kinase Stk.

Friend spleen focus-forming virus (SFFV) causes rapid erythroleukemia in mice due to expression of its unique envelope glycoprotein, gp55. Erythroid cells expressing SFFV gp55 proliferate in the absence of their normal regulator erythropoietin (Epo) because of constitutive activation of Epo signal transduction pathways. Although SFFV infects many cell types, deregulation of cell growth occurs only when SFFV infects erythroid cells, suggesting that these cells express unique proteins that the virus requires to mediate its biological effects.

Activation of the Jun N-terminal kinase pathway by friend spleen focus-forming virus and its role in the growth and survival of friend virus-induced erythroleukemia cells.

Members of the mitogen-activated protein kinase (MAPK) family, including Jun amino-terminal kinase (JNK) and extracellular signal-related kinase (ERK), play an important role in the proliferation of erythroid cells in response to erythropoietin (Epo). Erythroid cells infected with the Friend spleen focus-forming virus (SFFV) proliferate in the absence of Epo and show constitutive activation of Epo signal transduction pathways. We previously demonstrated that the ERK pathway was constitutively activated in Friend SFFV-infected erythroid cells, and in this study JNK is also shown to be constitutively activated.

Mass spectrometry of intact ribosomes.

The ability to maintain intact ribosomes in the mass spectrometer has enabled research into their changes in conformation and interactions. In the mass spectrometer, it is possible to induce dissociation of proteins from the intact ribosome and, in conjunction with atomic structures, to understand the factors governing their release. We have applied this knowledge to interpret the structural basis for release of proteins from ribosomes for which no high resolution structures are available, such as complexes with elongation factor G and ribosomes from yeast.

Mass spectrometry of ribosomes from Saccharomyces cerevisiae: implications for assembly of the stalk complex.

The acidic ribosomal P proteins form a distinct protuberance on the 60 S subunit of eukaryotic ribosomes. In yeast this structure is composed of two heterodimers (P1alpha-P2beta and P1beta-P2alpha) attached to the ribosome via P0. Although for prokaryotic ribosomes the isolation of a pentameric stalk complex comprising the analogous proteins is well established, its observation has not been reported for eukaryotic ribosomes.

Heteronuclear NMR investigations of dynamic regions of intact Escherichia coli ribosomes.

15N-(1)H NMR spectroscopy has been used to probe the dynamic properties of uniformly (15)N labeled Escherichia coli ribosomes. Despite the high molecular weight of the complex ( approximately 2.3 MDa), [(1)H-(15)N] heteronuclear single-quantum correlation spectra contain approximately 100 well resolved resonances, the majority of which arise from two of the four C-terminal domains of the stalk proteins, L7/L12.

Ex vivo and in vivo biological effects of a truncated form of the receptor tyrosine kinase stk when activated by interaction with the friend spleen focus-forming virus envelope glycoprotein or by point mutation.

The erythroleukemia-inducing Friend spleen focus-forming virus (SFFV) encodes a unique envelope protein, gp55, which interacts with the erythropoietin (Epo) receptor complex, causing proliferation and differentiation of erythroid cells in the absence of Epo. Susceptibility to SFFV-induced erythroleukemia is conferred by the Fv-2 gene, which encodes a short form of the receptor tyrosine kinase Stk/Ron (sf-Stk) only in susceptible strains of mice. We recently demonstrated that sf-Stk becomes activated by forming a strong interaction with SFFV gp55.

Protein-nucleic acid interactions and the expanding role of mass spectrometry.

Mass spectrometry methods are being developed that enable detection of protein interactions with nucleic acids. By mass measuring complexes a direct determination of the stoichiometry of protein-nucleic acid interactions is revealed. For more complex assemblies, using a different approach it is possible to gain information about subcomplexes and even the spatial arrangement of proteins in macromolecular machines.

Phospholipid complexation and association with apolipoprotein C-II: insights from mass spectrometry.

The interactions between phospholipid molecules in suspensions have been studied by using mass spectrometry. Electrospray mass spectra of homogeneous preparations formed from three different phospholipid molecules demonstrate that under certain conditions interactions between 90 and 100 lipid molecules can be preserved. In the presence of apolipoprotein C-II, a phospholipid binding protein, a series of lipid molecules and the protein were observed in complexes.

Expression of inducible nitric oxide synthase and elevation of tyrosine nitration of a 32-kilodalton cellular protein in brain capillary endothelial cells from rats infected with a neuropathogenic murine leukemia virus.

PVC-211 murine leukemia virus (MuLV) is a neuropathogenic variant of Friend MuLV (F-MuLV) which causes a rapidly progressive spongiform neurodegenerative disease in rodents. The primary target of PVC-211 MuLV infection in the brain is the brain capillary endothelial cell (BCEC), which is resistant to F-MuLV infection. Previous studies have shown that changes in the envelope gene of PVC-211 MuLV confer BCEC tropism to the virus.

Identification and characterization of a novel Ste20/germinal center kinase-related kinase, polyploidy-associated protein kinase.

A novel protein kinase, polyploidy-associated protein kinase (PAPK), was isolated using a subtraction cDNA library approach from a mouse erythroleukemia cell line that had been induced to polyploidy after serum withdrawal. PAPK shares homology with members of the Ste20/germinal center kinase family of protein kinases and is ubiquitously expressed as two spliced forms, PAPK-A and PAPK-B, that encode for proteins of 418 and 189 amino acids, respectively. The expression of endogenous PAPK-A protein increased after growth factor withdrawal in murine hematopoietic and fibroblast cells.