1,229 research outputs found
The (A)gamma-195 (C -> G) mutation in hereditary persistence of fetal hemoglobin is not associated with activation of a reporter gene in vitro
Hereditary persistence, of fetal hemoglobin is an uncommon, benign disorder in which the expression of gamma -globin genes persists into adult life. Several point mutations have been associated with the increased gamma -globin gene promoter activity. We evaluated the -195 (C-->G) mutation by a functional in vitro assay based on the luciferase reporter gene system. The results indicated that the increased promoter activity observed in vivo could not be reproduced in vitro, under the conditions employed, suggesting that other factors may be involved in the overexpression of the gamma -globin gene containing the -195 (C-->G) mutation. Furthermore: this is the first time that the -195 (C-->G) mutation of the (A)gamma -globin gene has been evaluated by in vitro gene expression.34448949
Resource dedication problem in a multi-project environment
There can be different approaches to the management of resources within
the context of multi-project scheduling problems. In general, approaches to multiproject scheduling problems consider the resources as a pool shared by all projects. On the other hand, when projects are distributed geographically or sharing resources between projects is not preferred, then this resource sharing policy may not be feasible. In such cases, the resources must be dedicated to individual projects throughout the project durations. This multi-project problem environment is defined here as the resource dedication problem (RDP). RDP is defined as the optimal dedication of resource capacities to different projects within the overall limits of the resources and with the objective of minimizing a predetermined objective function. The projects involved are multi-mode resource constrained project scheduling problems with finish to start zero time lag and non-preemptive activities and limited renewable and nonrenewable resources. Here, the characterization of RDP, its mathematical formulation and two different solution methodologies are presented. The first solution approach is a genetic algorithm employing a new improvement move called combinatorial auction for RDP, which is based on preferences of projects for resources. Two different methods for calculating the projects’ preferences based on linear and Lagrangian relaxation are proposed. The second solution approach is a Lagrangian relaxation based heuristic employing subgradient optimization. Numerical studies demonstrate that the proposed approaches are powerful methods for solving this problem
Levels of high-density lipoprotein cholesterol (HDL-C) among children with steady-state sickle cell disease
<p>Abstract</p> <p>Background</p> <p>The search for sickle cell disease (SCD) prognosis biomarkers is a challenge. These markers identification can help to establish further therapy, later severe clinical complications and with patients follow-up. We attempted to study a possible involvement of levels of high-density lipoprotein cholesterol (HDL-C) in steady-state children with SCD, once that this lipid marker has been correlated with anti-inflammatory, anti-oxidative, anti-aggregation, anti-coagulant and pro-fibrinolytic activities, important aspects to be considered in sickle cell disease pathogenesis.</p> <p>Methods</p> <p>We prospectively analyzed biochemical, inflammatory and hematological biomarkers of 152 steady-state infants with SCD and 132 healthy subjects using immunochemistry, immunoassay and electronic cell counter respectively. Clinical data were collected from patient medical records.</p> <p>Results</p> <p>Of the 152 infants investigated had a significant positive association of high-density lipoprotein cholesterol with hemoglobin (P < 0.001), hematocrit (P < 0.001) and total cholesterol (P < 0.001) and a negative significant association with reticulocytes (P = 0.046), leukocytes (P = 0.015), monocytes (P = 0.004) and platelets (P = 0.005), bilirubins [total bilirubin (P < 0.001), direct bilirubin (P < 0.001) and indirect bilirubin (P < 0.001], iron (P < 0.001), aminotransferases [aspartate aminotransferase (P = 0.004), alanine aminotransferase (P = 0.035)], lactate dehydrogenase (P < 0.001), urea (P = 0.030), alpha 1-antitrypsin (P < 0.001), very low-density lipoprotein cholesterol (P = 0.003), triglycerides (P = 0.005) and hemoglobin S (P = 0.002). Low high-density lipoprotein cholesterol concentration was associated with the history of cardiac abnormalities (P = 0.025), pneumonia (P = 0.033) and blood transfusion use (P = 0.025). Lipids and inflammatory markers were associated with the presence of cholelithiasis.</p> <p>Conclusions</p> <p>We hypothesize that some SCD patients can have a specific dyslipidemic subphenotype characterized by low HDL-C with hypertriglyceridemia and high VLDL-C in association with other biomarkers, including those related to inflammation. This represents an important step toward a more reliable clinical prognosis. Additional studies are warranted to test this hypothesis and the probably mechanisms involved in this complex network of markers and their role in SCD pathogenesis.</p
Blockade of microglial KATP-channel abrogates suppression of inflammatory-mediated inhibition of neural precursor cells
Microglia positively affect neural progenitor cell physiology through the release of inflammatory mediators or trophic factors. We demonstrated previously that reactive microglia foster KATP-channel expression and that blocking this channel using glibenclamide administration enhances striatal neurogenesis after stroke. In this study, we investigated whether the microglial KATP-channel directly influences the activation of neural precursor cells (NPCs) from the subventricular zone using transgenic Csf1r-GFP mice. In vitro exposure of NPCs to lipopolysaccharide and interferon-gamma resulted in a significant decrease in precursor cell number. The complete removal of microglia from the culture or exposure to enriched microglia culture also decreased the precursor cell number. The addition of glibenclamide rescued the negative effects of enriched microglia on neurosphere formation and promoted a ~20% improvement in precursor cell number. Similar results were found using microglial-conditioned media from isolated microglia. Using primary mixed glial and pure microglial cultures, glibenclamide specifically targeted reactive microglia to restore neurogenesis and increased the microglial production of the chemokine monocyte chemoattractant protein-1 (MCP-1). These findings provide the first direct evidence that the microglial KATP-channel is a regulator of the proliferation of NPCs under inflammatory conditions
Hepatitis B Vaccine Antibody Response and the Risk of Clinical AIDS or Death
Whether seroresponse to a vaccine such as hepatitis B virus (HBV) vaccine can provide a measure of the functional immune status of HIV-infected persons is unknown.This study evaluated the relationship between HBV vaccine seroresponses and progression to clinical AIDS or death. (HR 3.40; 95% CI, 1.39–8.32).
Sialic Acid Glycobiology Unveils Trypanosoma cruzi Trypomastigote Membrane Physiology.
Trypanosoma cruzi, the flagellate protozoan agent of Chagas disease or American trypanosomiasis, is unable to synthesize sialic acids de novo. Mucins and trans-sialidase (TS) are substrate and enzyme, respectively, of the glycobiological system that scavenges sialic acid from the host in a crucial interplay for T. cruzi life cycle. The acquisition of the sialyl residue allows the parasite to avoid lysis by serum factors and to interact with the host cell. A major drawback to studying the sialylation kinetics and turnover of the trypomastigote glycoconjugates is the difficulty to identify and follow the recently acquired sialyl residues. To tackle this issue, we followed an unnatural sugar approach as bioorthogonal chemical reporters, where the use of azidosialyl residues allowed identifying the acquired sugar. Advanced microscopy techniques, together with biochemical methods, were used to study the trypomastigote membrane from its glycobiological perspective. Main sialyl acceptors were identified as mucins by biochemical procedures and protein markers. Together with determining their shedding and turnover rates, we also report that several membrane proteins, including TS and its substrates, both glycosylphosphatidylinositol-anchored proteins, are separately distributed on parasite surface and contained in different and highly stable membrane microdomains. Notably, labeling for α(1,3)Galactosyl residues only partially colocalize with sialylated mucins, indicating that two species of glycosylated mucins do exist, which are segregated at the parasite surface. Moreover, sialylated mucins were included in lipid-raft-domains, whereas TS molecules are not. The location of the surface-anchored TS resulted too far off as to be capable to sialylate mucins, a role played by the shed TS instead. Phosphatidylinositol-phospholipase-C activity is actually not present in trypomastigotes. Therefore, shedding of TS occurs via microvesicles instead of as a fully soluble form
Scaling Patterns for QCD Jets
Jet emission at hadron colliders follows simple scaling patterns. Based on
perturbative QCD we derive Poisson and staircase scaling for final state as
well as initial state radiation. Parton density effects enhance staircase
scaling at low multiplicities. We propose experimental tests of our theoretical
findings in Z+jets and QCD gap jets production based on minor additions to
current LHC analyses.Comment: 36 pages, 16 figure
Carotid Plaque Age Is a Feature of Plaque Stability Inversely Related to Levels of Plasma Insulin
C-declination curve (a result of the atomic bomb tests in the
1950s and 1960s) to determine the average biological age of carotid
plaques.C
content by accelerator mass spectrometry. The average plaque age (i.e.
formation time) was 9.6±3.3 years. All but two plaques had formed
within 5–15 years before surgery. Plaque age was not associated with
the chronological ages of the patients but was inversely related to plasma
insulin levels (p = 0.0014). Most plaques were
echo-lucent rather than echo-rich (2.24±0.97, range 1–5).
However, plaques in the lowest tercile of plaque age (most recently formed)
were characterized by further instability with a higher content of lipids
and macrophages (67.8±12.4 vs. 50.4±6.2,
p = 0.00005; 57.6±26.1 vs. 39.8±25.7,
p<0.0005, respectively), less collagen (45.3±6.1 vs.
51.1±9.8, p<0.05), and fewer smooth muscle cells (130±31
vs. 141±21, p<0.05) than plaques in the highest tercile.
Microarray analysis of plaques in the lowest tercile also showed increased
activity of genes involved in immune responses and oxidative
phosphorylation.C, can improve our understanding of carotid
plaque stability and therefore risk for clinical complications. Our results
also suggest that levels of plasma insulin might be involved in determining
carotid plaque age
Altered Neurocircuitry in the Dopamine Transporter Knockout Mouse Brain
The plasma membrane transporters for the monoamine neurotransmitters dopamine, serotonin, and norepinephrine modulate the dynamics of these monoamine neurotransmitters. Thus, activity of these transporters has significant consequences for monoamine activity throughout the brain and for a number of neurological and psychiatric disorders. Gene knockout (KO) mice that reduce or eliminate expression of each of these monoamine transporters have provided a wealth of new information about the function of these proteins at molecular, physiological and behavioral levels. In the present work we use the unique properties of magnetic resonance imaging (MRI) to probe the effects of altered dopaminergic dynamics on meso-scale neuronal circuitry and overall brain morphology, since changes at these levels of organization might help to account for some of the extensive pharmacological and behavioral differences observed in dopamine transporter (DAT) KO mice. Despite the smaller size of these animals, voxel-wise statistical comparison of high resolution structural MR images indicated little morphological change as a consequence of DAT KO. Likewise, proton magnetic resonance spectra recorded in the striatum indicated no significant changes in detectable metabolite concentrations between DAT KO and wild-type (WT) mice. In contrast, alterations in the circuitry from the prefrontal cortex to the mesocortical limbic system, an important brain component intimately tied to function of mesolimbic/mesocortical dopamine reward pathways, were revealed by manganese-enhanced MRI (MEMRI). Analysis of co-registered MEMRI images taken over the 26 hours after introduction of Mn^(2+) into the prefrontal cortex indicated that DAT KO mice have a truncated Mn^(2+) distribution within this circuitry with little accumulation beyond the thalamus or contralateral to the injection site. By contrast, WT littermates exhibit Mn^(2+) transport into more posterior midbrain nuclei and contralateral mesolimbic structures at 26 hr post-injection. Thus, DAT KO mice appear, at this level of anatomic resolution, to have preserved cortico-striatal-thalamic connectivity but diminished robustness of reward-modulating circuitry distal to the thalamus. This is in contradistinction to the state of this circuitry in serotonin transporter KO mice where we observed more robust connectivity in more posterior brain regions using methods identical to those employed here
Association between hepatitis B vaccine antibody response and CD4 reconstitution after initiation of combination antiretroviral therapy in HIV-infected persons
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