562 research outputs found
The TLR4 D299G and T399I SNPs Are Constitutively Active to Up-Regulate Expression of Trif-Dependent Genes
Peer reviewedPublisher PD
Differential modulation of microglia superoxide anion and thromboxane B(2 )generation by the marine manzamines
BACKGROUND: Thromboxane B(2 )(TXB(2)) and superoxide anion (O(2)(-)) are neuroinflammatory mediators that appear to be involved in the pathogenesis of several neurodegenerative diseases. Because activated-microglia are the main source of TXB(2 )and O(2)(- )in these disorders, modulation of their synthesis has been hypothesized as a potential therapeutic approach for neuroinflammatory disorders. Marine natural products have become a source of novel agents that modulate eicosanoids and O(2)(- )generation from activated murine and human leukocytes. With the exception of manzamine C, all other manzamines tested are characterized by a complex pentacyclic diamine linked to C-1 of the β-carboline moiety. These marine-derived alkaloids have been reported to possess a diverse range of bioactivities including anticancer, immunostimulatory, insecticidal, antibacterial, antimalarial and antituberculosis activities. The purpose of this investigation was to conduct a structure-activity relationship study with manzamines (MZ) A, B, C, D, E and F on agonist-stimulated release of TXB(2 )and O(2)(- )from E. coli LPS-activated rat neonatal microglia in vitro. RESULTS: The manzamines differentially attenuated PMA (phorbol 12-myristate 13-acetate)-stimulated TXB(2 )generation in the following order of decreasing potency: MZA (IC(50 )<0.016 μM) >MZD (IC(50 )= 0.23 μM) >MZB (IC(50 )= 1.6 μM) >MZC (IC(50 )= 2.98 μM) >MZE and F (IC(50 )>10 μM). In contrast, there was less effect on OPZ (opsonized zymosan)-stimulated TXB(2 )generation: MZB (IC(50 )= 1.44 μM) >MZA (IC(50 )= 3.16 μM) >MZC (IC(50 )= 3.34 μM) >MZD, MZE and MZF (IC(50 )>10 μM). Similarly, PMA-stimulated O(2)(- )generation was affected differentially as follows: MZD (apparent IC(50)<0.1 μM) >MZA (IC(50 )= 0.1 μM) >MZB (IC(50 )= 3.16 μM) >MZC (IC(50 )= 3.43 μM) >MZE and MZF (IC(50 )>10 μM). In contrast, OPZ-stimulated O(2)(- )generation was minimally affected: MZB (IC(50 )= 4.17 μM) >MZC (IC(50 )= 9.3 μM) >MZA, MZD, MZE and MZF (IC(50 )> 10 μM). From the structure-activity relationship perspective, contributing factors to the observed differential bioactivity on TXB(2 )and O(2)(- )generation are the solubility or ionic forms of MZA and D as well as changes such as saturation or oxidation of the β carboline or 8-membered amine ring. In contrast, the fused 13-membered macrocyclic and isoquinoline ring system, and any substitutions in these rings would not appear to be factors contributing to bioactivity. CONCLUSION: To our knowledge, this is the first experimental study that demonstrates that MZA, at in vitro concentrations that are non toxic to E. coli LPS-activated rat neonatal microglia, potently modulates PMA-stimulated TXB(2 )and O(2)(- )generation. MZA may thus be a lead candidate for the development of novel therapeutic agents for the modulation of TXB(2 )and O(2)(- )release in neuroinflammatory diseases. Marine natural products provide a novel and rich source of chemical diversity that can contribute to the design and development of new and potentially useful anti-inflammatory agents to treat neurodegenerative diseases
Enforcement of State Indoor Tanning Laws in the United States
Introduction Twenty-eight US states have passed legislation for indoor tanning facilities. To our knowledge, whether these state laws are actually enforced has not been evaluated previously in all 28 states. Therefore, we interviewed key informants in these states to assess enforcement practices. Methods Two trained interviewers used a structured survey instrument to interview 28 key informants who were knowledgeable about enforcement practices for laws regarding indoor tanning. Respondents provided information specific to the most populous city in their states. Results Licensure for indoor tanning businesses was required in 22 of the 28 cities. Slightly less than half of the cities gave citations to tanning facilities that violated state law. Approximately 32% of the cities did not inspect indoor tanning facilities for compliance with state law, and another 32% conducted inspections less than annually. Of those cities that inspected at all, most conducted unannounced inspections. Conclusion The relatively low rates of annual inspections and citations are of concern. We recommend that future studies assess whether legislation, enforcement practices, or a combination of the 2 affects the practices of indoor tanning facilities or of consumers
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Market-Based Environmental Management: Issues in Implementation
Increasingly, efforts to protect integral features of the natural environment that are essential to human well being face a double challenge. First, the magnitude of some conventional and emerging threats to environmental quality is growing, despite solid progress in controlling some causes. This is particularly the concern on a global scale in terms of atmospheric changes and loss of biological diversity. Second, easily-implemented uniform control methods using feasible technologies or other direct regulatory approaches are already in place for many pollution and resource management problems in the United States. Additional progress with so-called command and control policies can be expensive and disruptive, and thus counter productive to overall economic well being. This type of dilemma is common where environmental deterioration results from diffuse and complex causes inherent in technically-advanced high-consumption industrial societies such as the U.S. Solutions to these types of environmental problems are complicated by the diffuse benefits which obscures the net gains of additional controls that have concentrated and highly visible costs. Given this double bind, many policy analysts and academics have for years advocated more cost-effective and flexible approaches relying on market forces to further some environmental management objectives. Although market-based theory and practical environmental policy are still far apart, the incremental approach to environmental policymaking since the late seventies has resulted in some market-type innovations within traditional regulatory frameworks at all levels of government. The most prominent examples are the Environmental Protection Agency's (EPA) air emissions trading program and the recently enacted sulfur dioxide allowance trading program under the 1990 Clean Air Act Amendments
Normoalbuminuric Diabetic Kidney Disease in the U.S. Population
This study sought to compare the prevalence and modifying factors of normoalbuminuric (NA) versus albuminuric (ALB) CKD in the U.S. diabetic and nondiabetic populations
Performance of a Limiting-Antigen Avidity Enzyme Immunoassay for Cross-Sectional Estimation of HIV Incidence in the United States
Background: A limiting antigen avidity enzyme immunoassay (HIV-1 LAg-Avidity assay) was recently developed for cross-sectional HIV incidence estimation. We evaluated the performance of the LAg-Avidity assay alone and in multi-assay algorithms (MAAs) that included other biomarkers. Methods and Findings: Performance of testing algorithms was evaluated using 2,282 samples from individuals in the United States collected 1 month to >8 years after HIV seroconversion. The capacity of selected testing algorithms to accurately estimate incidence was evaluated in three longitudinal cohorts. When used in a single-assay format, the LAg-Avidity assay classified some individuals infected >5 years as assay positive and failed to provide reliable incidence estimates in cohorts that included individuals with long-term infections. We evaluated >500,000 testing algorithms, that included the LAg-Avidity assay alone and MAAs with other biomarkers (BED capture immunoassay [BED-CEIA], BioRad-Avidity assay, HIV viral load, CD4 cell count), varying the assays and assay cutoffs. We identified an optimized 2-assay MAA that included the LAg-Avidity and BioRad-Avidity assays, and an optimized 4-assay MAA that included those assays, as well as HIV viral load and CD4 cell count. The two optimized MAAs classified all 845 samples from individuals infected >5 years as MAA negative and estimated incidence within a year of sample collection. These two MAAs produced incidence estimates that were consistent with those from longitudinal follow-up of cohorts. A comparison of the laboratory assay costs of the MAAs was also performed, and we found that the costs associated with the optimal two assay MAA were substantially less than with the four assay MAA. Conclusions: The LAg-Avidity assay did not perform well in a single-assay format, regardless of the assay cutoff. MAAs that include the LAg-Avidity and BioRad-Avidity assays, with or without viral load and CD4 cell count, provide accurate incidence estimates
Five sepharose-bound ligands for the chromatographic purification of Clostridium collagenase and clostripain
Social media data have provoked a mixed response from researchers. While there is great enthusiasm for this new source of social data – Twitter data in particular – concerns are also expressed about their biases and unknown provenance and, consequently, their credibility for social research. This article seeks a middle path, arguing that we must develop better understanding of the construction and circulation of social media data to evaluate their appropriate uses and the claims that might be made from them. Building on sociotechnical approaches, we propose a high-level abstraction of the ‘pipeline’ through which social media data are constructed and circulated. In turn, we explore how this shapes the populations and samples that are present in social media data and the methods that generate data about them. We conclude with some broad principles for supporting methodologically informed social media research in the future
a global network of chronic kidney disease cohorts
Background Chronic kidney disease (CKD) is a global health burden, yet it is
still underrepresented within public health agendas in many countries. Studies
focusing on the natural history of CKD are challenging to design and conduct,
because of the long time-course of disease progression, a wide variation in
etiologies, and a large amount of clinical variability among individuals with
CKD. With the difference in health-related behaviors, healthcare delivery,
genetics, and environmental exposures, this variability is greater across
countries than within one locale and may not be captured effectively in a
single study. Methods Studies were invited to join the network. Prerequisites
for membership included: 1) observational designs with a priori hypotheses and
defined study objectives, patient-level information, prospective data
acquisition and collection of bio-samples, all focused on predialysis CKD
patients; 2) target sample sizes of 1,000 patients for adult cohorts and 300
for pediatric cohorts; and 3) minimum follow-up of three years. Participating
studies were surveyed regarding design, data, and biosample resources. Results
Twelve prospective cohort studies and two registries covering 21 countries
were included. Participants age ranges from >2 to >70 years at inclusion, CKD
severity ranges from stage 2 to stage 5. Patient data and biosamples (not
available in the registry studies) are measured yearly or biennially. Many
studies included multiple ethnicities; cohort size ranges from 400 to more
than 13,000 participants. Studies’ areas of emphasis all include but are not
limited to renal outcomes, such as progression to ESRD and death. Conclusions
iNET-CKD (International Network of CKD cohort studies) was established, to
promote collaborative research, foster exchange of expertise, and create
opportunities for research training. Participating studies have many
commonalities that will facilitate comparative research; however, we also
observed substantial differences. The diversity we observed across studies
within this network will be able to be leveraged to identify genetic,
behavioral, and health services factors associated with the course of CKD.
With an emerging infrastructure to facilitate interactions among the
investigators of iNET-CKD and a broadly defined research agenda, we are
confident that there will be great opportunity for productive collaborative
investigations involving cohorts of individuals with CKD
A Comparison of Two Measures of HIV Diversity in Multi-Assay Algorithms for HIV Incidence Estimation
Background:
Multi-assay algorithms (MAAs) can be used to estimate HIV incidence in cross-sectional surveys. We compared the performance of two MAAs that use HIV diversity as one of four biomarkers for analysis of HIV incidence.
Methods:
Both MAAs included two serologic assays (LAg-Avidity assay and BioRad-Avidity assay), HIV viral load, and an HIV diversity assay. HIV diversity was quantified using either a high resolution melting (HRM) diversity assay that does not require HIV sequencing (HRM score for a 239 base pair env region) or sequence ambiguity (the percentage of ambiguous bases in a 1,302 base pair pol region). Samples were classified as MAA positive (likely from individuals with recent HIV infection) if they met the criteria for all of the assays in the MAA. The following performance characteristics were assessed: (1) the proportion of samples classified as MAA positive as a function of duration of infection, (2) the mean window period, (3) the shadow (the time period before sample collection that is being assessed by the MAA), and (4) the accuracy of cross-sectional incidence estimates for three cohort studies.
Results:
The proportion of samples classified as MAA positive as a function of duration of infection was nearly identical for the two MAAs. The mean window period was 141 days for the HRM-based MAA and 131 days for the sequence ambiguity-based MAA. The shadows for both MAAs were <1 year. Both MAAs provided cross-sectional HIV incidence estimates that were very similar to longitudinal incidence estimates based on HIV seroconversion.
Conclusions:
MAAs that include the LAg-Avidity assay, the BioRad-Avidity assay, HIV viral load, and HIV diversity can provide accurate HIV incidence estimates. Sequence ambiguity measures obtained using a commercially-available HIV genotyping system can be used as an alternative to HRM scores in MAAs for cross-sectional HIV incidence estimation
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